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Posters Presented at the 21st Joint Meeting of the International Society of Dermatopathology, February 14, 2018, The Westin San Diego, San Diego, California, USA

The American Journal of Dermatopathology: June 2018 - Volume 40 - Issue 6 - p e80–e94
doi: 10.1097/DAD.0000000000001163
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An Unusual Presentation of Porphyria Cutanea Tarda

Prajesh Adhikari, MD,* Joseph Pierson, MD,† and Deborah Cook, MD*

Departments of *Pathology and †Dermatology, University of Vermont Medical Center, Burlington, VT.

Porphyria cutanea tarda (PCT) is the most common porphyria and the result of decreased uroporphyrinogen decarboxylase. Cutaneous PCT usually manifests as increased photosensitivity, skin fragility, blisters, erosions, and crusts. We present a case of a 77-year-old male who presented to dermatology clinic for non-tender ulcers of the scalp and face that increased in size and quantity since appearing 1 year prior. He experienced other symptoms including dysphagia secondary to esophageal stricture, calcinosis, and 60-pound weight loss. Antibody testing, including ANA, dsDNA, Smith, SSA/SSB, Scl70, Jo, RNP, and RNA polymerase 3 was negative. Along with absence of arthritis and Raynaud's, these findings favored a non-autoimmune etiology. Multiple shave biopsies showed epidermal hyperplasia with hyperkeratosis, occasional ulcer, dermal lymphoplasmacytic infiltrate, calcification, and scar formation. He had been trialed on methotrexate and diltiazem with no appreciable improvement. Urine and fecal porphyrins, including uroporphyrin and isocoproporphyrin, were elevated, consistent with a diagnosis of PCT. He has begun phlebotomy treatments and hydroxychloroquine. This unusual presentation of PCT underscores the utility of laboratory testing in confirming diagnosis.

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Skin Involvement in Chronic Lymphocytic Leukemia: Case Report and Review of Literature

Hermineh Aramin, MD and Gunjan Gupta, MD

Department of Pathology, Danbury Hospital, CT.

Chronic lymphocytic leukemia (CLL) is a neoplasm characterized by the accumulation of mature monoclonal B cells in blood. It commonly involves bone marrow and lymphoid tissues such as spleen, lymph nodes and Waldeyer ring. Involvement of the skin by the leukemia cells is a rare occurrence. Although cutaneous lesions in patients with CLL account for up to 25%, they are comprised of other malignancies (SCC, BCC and Merkel cell tumor), nonmalignant disorders (infectious or hemorrhagic origin) as well as leukemic CLL skin infiltrates (leukemia cutis). The few cases of skin involvement by CLL described in the literature presented with solitary or generalized papules, nodules, plaques and large masses. We report a case of 72 year old male with recent diagnosis of CLL in peripheral blood (confirmed by flow cytometry and showing trisomy 12 on conventional cytogenetics) presenting with two small nodular cutaneous lesions on the cheek and forearm. Skin biopsies of both lesions revealed involvement by secondary leukemia cutis by immunohistologic evaluation. We also provide a review of literature of CLL cases involving the skin.

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Another Rare Case of Superficial Cd34-Positive Fibroblastic Tumor

Mary M. Braden, MD, FAAD, John M. Childs, MD, FCAP, and David M. Rogers, MD, FCAP

Department of Pathology and Laboratory Services, Walter Reed National Military Medical Center, Bethesda, MD.

A 23-year-old male presented with a one year history of a mass on the dorsum of the right second toe that was steadily growing and painful with friction, but otherwise asymptomatic. Exam revealed a 3.5 × 3.5 cm purple mass that was not adherent to underlying tendons. Excisional biopsy demonstrated a highly atypical spindle cell neoplasm composed of cells with abundant, glassy, eosinophilic cytoplasm and prominent nucleoli. Mitotic figures were rare, with occasional background osteoclast-like giant cells. Myxoid degeneration was not seen. The cells of interest were diffusely positive for CD34, vimentin, AE1/AE3, and CD10, and focally positive for CK8/18 and calponin, and negative for EMA, S100, SOX10, HMB45, CD31, ERG, factor VII related antigen, factor XIIIa, SMA, desmin, MyoD1, CD163, CK5/6, and ALK1. INI-1 expression was retained. Ki-67 expression was moderately increased. These findings are consistent with a diagnosis of superficial CD34-positive fibroblastic tumor of intermediate (borderline) malignancy. This entity has only recently been described, and has received little attention in the dermatopathology literature. These low-grade neoplasms, often classified previously as “low grade sarcomas” or “low grade malignant fibrous histiocytomas,” occur in the superficial soft tissue with significant cellular pleomorphism, and a fascicular growth pattern of spindle cells with diffuse CD34 positivity.

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Pseudomyogenic Hemangioendothelioma Presenting as a Painful Cutaneous Nodule

Jill Browning, Elizabeth Bressler, Rex Bentley, and Kristen Paral

Department of Pathology, Duke University, Durham, NC.

Pseudomyogenic hemangioendothelioma (PMH) is a rare endothelial tumor that often presents as multiple nodules in the lower extremities of young men. Here we describe a case of a 39-year-old woman who presented with a single painful nodule on her left upper leg that was initially treated as an abscess. Imaging studies revealed abnormalities in the subcutaneous and muscular planes, further identified during surgery as multiple discontiguous nodules. Microscopic examination revealed an infiltrative mass involving the dermis and subcutis, consisting of plump spindled to epithelioid cells with vesicular nuclei. Nuclear atypia was limited. Characteristic rhabdomyoblast-like cells were identified. Additionally, numerous neutrophils were observed. Immunohistochemistry showed expression of both epithelial (cytokeratin cocktail) and vascular markers (ERG, FLI-1, and CD31). INI-1 expression was retained. Desmin and CD34 stains were negative. Expression of both epithelial and vascular markers, along with INI-1 retention, clinches the diagnosis of PMH. The differential diagnosis includes epithelioid sarcoma and sarcomatoid carcinoma, which must be excluded immunohistochemically. Accurate diagnosis of PMH presents a challenge due to its ability to simulate other neoplasms and its remarkable rarity in the skin.

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Calcium Hydroxyapatite Injection Mimicking an Unusal Lesion on the Dorsum of the Hand

Ryan Campbell

Department of Pathology, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR; and Nicholas Whitling—Dermpath Diagnostics of Atlanta, Marietta, GA.

Calcium hydroxyapatite injectable fillers are commonly used for aesthetic improvement of creases, depressions, or areas with poor collagen production. The side effects are often minor, which include swelling, redness, and possible infection at the site of injection. We report a 59 year old Caucasian female who presented with a firm pink subcutaneous nodule on the dorsum of the right hand with clinical characteristics of a xanthoma. A punch biopsy revealed numerous polarizable round deposits surrounded by a foreign-body granulomatous response in the dermis. Although the dorsal hand is not always considered by the pathologist as a site typically injected with fillers, this site is often a cosmetic concern in the aging patient. Our case highlights a less-considered differential diagnostic possibility in the work-up of a subcutaneous nodule on the dorsum hand.

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Late-Onset Focal Dermal Elastosis Mimicking Pseudoxanthoma Elasticum

Aegean Chan, MD,*,† Barney Kenet, MD,‡ Kenneth Shulman, MD,† and Mark Jacobson, MD*,†

*Montefiore Medical Center, Department of Pathology, Bronx, NY; †Dermpath Diagnostics, Port Chester, NY; and ‡Weill Cornell Department of Dermatology, New York, NY.

We present a case of a 70-year old woman with asymptomatic skin lesions in the bilateral axillae for 5 years. Skin examination revealed white papules coalescing into plaques with a cobblestoned appearance. A biopsy revealed prominent elastic fibers in the deep reticular dermis. EVG and Orcein stains highlighted foci of thickened and clumped elastic fibers. These findings are consistent with late-onset focal dermal elastosis, a rare disorder of altered elastic tissue. The clinical lesions mimic pseudoxanthoma elasticum (PXE) and appear sporadically in the flexural areas of healthy adults in their seventh to ninth decade. The histopathologic hallmark is that of thickened elastic fibers in the deep reticular dermis with no evidence of fragmentation or calcification. These unique histopathologic features allow for differentiation of this entity from PXE, dermatofibrosis lenticularis disseminata, and fibroelastolytic papulosis. Although the clinical presentation of white to yellow plaques with a cobblestoned appearance is classically associated with PXE, several mimickers should be considered in the differential diagnosis.

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Phosphaturic Mesenchymal Tumor: A Report of 5 Cases

Ijeuru Chikeka, MD and Fabrizio Remotti, MD

Columbia University Medical Center, New York, NY.

Phosphaturic mesenchymal tumors are rare benign neoplasms that produce phosphaturic hormones which lead to uncontrolled renal loss of phosphate and subsequent osteomalacia. We report 5 cases of tumor induced osteomalacia in 3 men and 2 women from ages 42 to 64 who developed debilitating generalized bone and joint pain, muscle weakness, and pathologic fractures. The patients had been symptomatic an average of 4.2 years prior to identification and excision of the tumor. The tumors were localized in the soft tissue of the distal lower extremities, the mandible, and the soft tissue surrounding the right hip. The tumors ranged in size from 0.7 to 3.0 cm in greatest dimension. Histologic examination of all 5 cases showed mononuclear spindle cells within a cartilaginous background with grungy calcification and hemangiopericytoma-like vessels. Post excision, all patients experienced a significant improvement in their symptoms and normalization of their serum phosphorus levels. In 2 patients, FGF-23, a phosphate regulating hormone, was found to be elevated prior to excision and became undetectable post-excision. In adults with osteomalacia and hypophosphatemia, a high index of suspicion can lead to earlier diagnosis and treatment, preventing irreversible morbidity.

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A Case of Indeterminate Cell Histiocytosis in a 2 Year Old Girl Triggered By a URI

Ijeuru Chikeka, MD, Julia Gittler, MD, and David Silvers, MD

Columbia University Medical Center, NY, NY.

We report a case of a 2 year old female who presented with a persistent erythematous papular rash on the extremities, bilateral buttocks, and proximal thighs after a URI. She experienced a similar rash 6 months prior which resolved spontaneously. A skin biopsy showed a superficial and deep predominantly perivascular infiltrate of lymphocytes and mononuclear cells with histiocytoid cytology, abundant eosinophilic cytoplasm, oval nuclei with irregular nuclear contours and frequent longitudinal grooves resembling coffee beans. Immunohistochemical staining was positive for S100, CD1-A, CD68, and CD163 and negative for Langerin. DIF testing was negative. These findings were most consistent with Indeterminate Cell Histiocytosis (ICH), a rare disease characterized by proliferation of histiocytes with a mixed immunohistochemical phenotype between Langerhans cells and non-Langerhans histiocytes. The clinical and histologic features of this entity, with special attention to the pediatric population, are described. Awareness of the clinico-morphologic spectrum of ICH is necessary to prevent misdiagnosis and to guide workup including investigation of organ involvement and associated hematologic neoplasms.

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Leukemia Cutis Masquerading as Pityriasis Rosea

Jette Hooper,* Peter Shen,† Frank Santoro,† Woo Cheal Cho,† and Zendee Elaba†

*Frank H. Netter MD School of Medicine at Quinnipiac University, North Haven, CT; and †Hartford Healthcare, Hartford, CT.

Leukemia Cutis (LC) is leukemic cell infiltration into the epidermis, dermis, and subcutis. Only 3% of patients with AML develop LC mostly in patients with known AML. We report a patient presenting with a rash clinically resembling pityriasis rosea and drug reaction. The patient is a 93-year-old female with hypertension, hyperlipidemia, and hypothyroidism who presented with an erythematous rash clinically assessed as pityriasis rosea. Oral steroids were initiated and after two weeks with no improvement, a drug rash was then suspected. During follow up, CBC revealed anemia, leukocytosis, and thrombocytopenia prompting hospital admission. While admitted, the patient displayed indurated papules coalescing into plaques on the trunk, neck, and extremities. Biopsy revealed dermal infiltration by atypical mononuclear cells with ovoid to indented nuclei and increased cytoplasm. By immunohistochemistry the infiltrate was positive for myelomonocytic markers CD15, CD33, CD45, CD68, CD163 but negative for myeloperoxidase, CD34, and CD117. Peripheral blood smear and flow cytometry confirmed the diagnosis of AML.

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Leukocytoclastic Vasculitis Presenting in an Elderly Male Following Influenza Vaccination

Michael DeWall, DO,* Miki Lindsey, MS-3,* Carmen Meeker, PA,† and Jennifer Kaley, MD*

*University of Arkansas for Medical Sciences, Little Rock, AR; and †Arkansas Skin Cancer Center, Searcy, AR.

Leukocytoclastic vasculitis (LCV) is a small vessel vasculitis that presents as palpable purpura. It can be triggered by infection, medication, or unknown insult. We present a case of LCV following influenza vaccination. An 82 year-old male presented with a pruritic, “burning” rash which arose one week prior. Recent history included influenza vaccination two weeks prior. Dermatologic examination revealed an erythematous maculopapular rash involving the neck, chest, and bilateral upper extremities. Histologic examination of punch biopsies from the medial and lateral left shoulder revealed a neutrophilic infiltrate involving the vessels of the superficial vascular plexus, extravasation of erythrocytes into the surrounding dermis, and extensive nuclear debris. The endothelial cells within the affected vessels appeared enlarged and damaged. A diagnosis of leukocytoclastic vasculitis was rendered. The development of various types of vasculitides occurring in timely association with influenza vaccination has been rarely reported in the literature previously. This report raises awareness of LCV as a potential and underrecognized adverse effect following influenza vaccination.

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Spiradenocylindrocarcinoma: Report of a Fatal Case with Genomic Anaylsis

Scott Diamond, MD,* Cameron Wales, MD,* Sarah Murray, PhD, and Brian Hinds, MD†

Departments of *Pathology, and †Dermatology, UCSD, San Diego, CA.

Background: Spiradenocylindrocarcinoma is a rare hybrid adnexal tumor.

Report: In 2008, a 50-year-old man presented with 10 cm mass emanating from the R-preauricular and parotid region interpreted as “dermal cylindroma.” In 2010, a 3.4 cm tumor recurred in the periauricular cartilage/external auditory canal. Subsequent extirpation had positive margins, but he declined treatment. In 2016, biopsy of a 7 cm persistence in the right mastoid region revealed spiradenomacarcinoma, cylindromacarcinoma, and basal cell adenocarcinoma-like foci. p53 was positive with Ki67 proliferative index (>20%). NGS was performed with microarray analysis. Potential driver mutations (DNMT3A, ERCC4, NOTCH1) and chromosomal deletions in 5q31.2-q33.3 (CSF1R; PDGFRB; CD74; ITKlEBF1), 7q21.2-q31.31 (CDK6; TRRAP; CUX1; PIK3CG; MET), 7q36.1 and 13q22.2—q31.1 were identified. Widespread metastasis (brain, lung) led to the patient's death.

Discussion: Notably, CYLD and p53 mutations were absent in spiradenocylindrocarcinoma, which corroborates prior discordance between p53 immunohistochemistry and p53-mutation. Deleterious mutations in DNMT3A are known to mediate poor prognosis in other solid tumors. Similarly, widespread epigenetic modification may propagate genomic instability/transformation in spiradenocylindrocarcinoma.

Conclusions: This represents the first genomic analysis of spiradenocylindrocarcinoma.

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Comparison of Automated-RNA and DNA-Based-ISH for Detection of Low Risk (LR)-HPV in Challenging Genital Lesions

Julio A. Diaz-Perez, Telma Perez, Antoinette B. Thomas, and Thomas L. Cibull

NorthShore University HealthSystem, Evanston, IL.

Background: HPV is a sexually transmitted agent for which the reliable detection is significant. The distinction between condyloma acuminatum (CA) and non-HPV keratinocytic-lesions may be problematic if the HPV-cytopathic changes are subtle. DNA-based-ISH (D-ISH) for detection of LR-HPV has been utilized. Recently, automated mRNA-based-ISH (R-ISH) for detection of LR-HPV was introduced. The purpose of this study is to compare R-ISH with D-ISH against similar genotypes.

Method: Six cases of clinical CA versus benign keratosis in which the viral HPV cytopathic changes were equivocal were studied. Each case was analyzed by D-ISH (Biocare-cocktail) and R-ISH (Ventana-cocktail) against LR-HPV genotypes (6 and 11). Both methods were performed on FFPE sections. Chromogenic-nuclear reactivity was evaluated with appropriate controls.

Results: Four patients were male and two female. Ages ranged from 32-months to 55-years (median 44-years). LR-HPV was detected with D-ISH in 100% of cases and with R-ISH in 50%. D-ISH signals were visible at 4 and 10x in 100% of cases, facilitating unanimous inter-observer reproducibility (kappa = 1). R-ISH signals were observed at low power in 50% of cases, and inter-observer reproducibility was lower (0.5).

Conclusions: In this study the observed rates of LR-HPV detection with D-ISH were higher when compared with R-ISH using cocktails against the same genotypes. This suggests that automated D-ISH sensitivity surpasses R-ISH. Additionally, D-ISH provided better staining, with positive cases identifiable at low and medium power.

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Development of Pityriasis Amiantacea After Valproic Acid Therapy

Julio A. Diaz-Perez, Joel C. Joyce, Thomas L. Cibull, and Thomas A. Victor

NorthShore University HealthSystem, Evanston, IL.

Introduction: Pityriasis amiantacea (PA) is an inflammatory dermatosis of hair bearing skin characterized by adherent thick scales, which surround and matt the hairs. The etiology of PA is thought to be multifactorial and can be associated with drugs and environmental factors in the context of scaly dermatoses. We present the first case to our knowledge of PA developing after valproic acid (VA) use.

Case report: A 16 year-old male with controlled seborrheic dermatitis and epilepsy developed pruritic, erythematous scaly plaques of the scalp, axillae, and pubis after beginning VA.

Results: A scalp biopsy showed psoriasiform hyperplasia with parakeratosis, hyperkeratosis, and prominent spongiosis of the epidermis and infundibula. The patient was treated with clobetasol, salicylic acid and ketoconazole shampoos and VA was switched to zonisamide. Two weeks later significant improvement was documented.

Conclusions: VA is a short-chain fatty acid with inhibitory activity on GSK3β and subsequent activation of the Wnt/β-catenin pathway leading to keratinocyte proliferation and rapid epidermal turnover. The temporal relationship between VA use and PA in our patient infers that VA played a direct role in the development of PA.

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A Case of Intermetacarpal Masson Tumor

Ismail Elbaz-Younes,* Andre Kajdacsy-Balla,* Talwar Parkash,† Gautam Malhotra,‡ and Marylee Braniecki*

Departments of *Pathology, †Radiology, and ‡Surgery, University of Illinois at Chicago, Chicago, IL.

Masson tumor, also known as intravascular papillary endothelial hyperplasia, is an exuberant intraluminal organization associated with recanalization of thrombus and papillary formation. Masson tumor typically occurs within distended vessels, preexisting varices and hemangiomas. It occurs most commonly in head, neck and fingers. We share a case of a 23-year-old female who presented with a dorsal hand cyst for 2 months. She experienced pain with activities. Imaging of the hand showed 1.5 × 0.5 cm soft tissue density over the dorsal aspect of the hand, located between the distal metacarpal bones. Histopathology revealed an aneurysmic venous malformation with a spindle cell proliferation showing masson tumor morphology composed of endothelial cells forming papillary structures. It showed neither atypia nor atypical mitotic activity. There was immuno-uptake with factor VIII, CD34, and CD31 indicating the vascular nature of the tumor. The treatment of Masson tumor is complete excision. We share this case of a Masson tumor occurring in an unusual intermetacarpal location of the hand.

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Stellate Tender Plaques: A Classic Case With Classic Histologic Findings

A. Corcimaru,* K. Ellison,† J. W. Roman,‡ A. Radfar,† and H. B. Pasieka†

Departments of *Internal Medicine, and †Dermatology, Washington Hospital Center, Washington, DC; and ‡Walter Reed National Military Medical Center, Bethesda, MD.

We present a case of calciphylaxis with a literature review. A 55-year-old male with a past medical history of HIV and a 12-year history of ESRD on hemodialysis presented with a 3-week history of tender ulcers on his back, leukocytosis and tachycardia. Physical exam revealed multiple scattered violaceous patches and indurated, purpuric plaques, as well as many stellate necrotic ulcers of various sizes with overlying black eschar and rim of erythema over the patient's back and proximal extremities. The patient also had generalized skin induration with a peau d'orange appearance on the lower back and anterior lower abdomen. A biopsy was significant for thromboembolic vasculopathy. Von Kossa stain revealed calcification of medium size vessels, calcium salt deposition in the wall of small vessels and perieccrine calcium deposition. A diagnosis of calciphylaxis was made. The patient was initially treated with intravenous sodium thiosulfate with minimal improvement and was later transitioned to comfort care.

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Epstein-Barr Virus-Positive Lymphomatoid Papulosis

Lacey Elwyn, DO,* Gregory Barron, MD,† Samuel Eckert, DO,‡ Eugene Sanik, DO,§ Carlos Ricotti, MD,¶ and Laszlo Karai, MD, PhD‖

*Dermatopathology Fellow/Dermatologist, Larkin Community Hospital, Miami, FL; †Dermatologist, Romagosa Dermatology Group LLC, Stuart, FL; ‡Dermatologist, Minnesota Dermatology, Plymouth, MN; §Dermatologist, James A. Haley Veterans Hospital, Tampa, FL; ¶Dermatopathologist/Dermatologist, Vitro Molecular Laboratory, Miami, FL; and ‖Dermatopathologist, Aurora Diagnostics, Global Pathology Laboratory, Miami Lakes, FL.

We report a case of an 83 year-old male, with a two-year history of recurring and remitting ulcerative papulo-nodules and no systemic involvement. Skin biopsies revealed an epidermotropic and diffuse dermal infiltrate of CD7, CD8, and CD30 positive atypical lymphoid cells, which were negative for CD56, ALK-1, and EMA staining. EBER in situ hybridization was positive in tumor cells. Clinical evaluation and imaging failed to demonstrate oro-pharyngeal involvement. In light of these findings, the diagnosis of a primary cutaneous Epstein-Barr virus associated lymphomatoid papulosis is favored. The relapsing and remitting nature, indolent clinical course, lack of oro-pharyngeal symptomatology, the negative imaging, negative CD56 staining, together with positive T-cell clonality support the diagnosis. We report the first case of lymphomatoid papulosis associated with Epstein-Barr virus infection. This condition is rare although similar reports have been seen in Asian patients with primary cutaneous anaplastic large cell lymphoma.

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Metastatic Pancreatic Adenocarcinoma to the Penis

Jake Fagan, MD, Nicholas Sebes, MD, Eric Hossler, MD, and Zong-Ming Chen, MD

Departments of Dermatology and Pathology, Geisinger Medical Center, Danville, PA.

The authors declare no conflicts of interest.

Pancreatic adenocarcinoma cutaneous metastasis is a rare skin finding with poor prognosis. Secondary penile carcinoma is rare, most commonly originating from urogenital metastasis. We present a unique case of a patient with known pancreatic cancer and new penile nodules. A 79-year-old male presented to clinic with a 3-week history of painful cutaneous nodules on the penile shaft and glans. His medical history included pancreatic adenocarcinoma with known colonic invasion. Physical exam showed 1–2 cm yellow/pink nodules on the glans, corona, and shaft of the penis. Biopsy of a glans nodule showed atypical glands and ducts throughout the dermis positive for CK20 and CK7 stains, and patchy CDX2 staining, consistent with pancreatic adenocarcinoma. Pancreatic adenocarcinoma with penile metastasis is an exceedingly rare diagnosis. Skin lesions are most often found around the umbilicus and are associated with disseminated disease. Histological review most commonly shows adenocarcinoma with moderate to poor differentiation, CK-7, CK-19 and CA 19-9 stains are positive with CK-20 showing variable positivity. Treatment is often palliative to alleviate pain or urinary obstruction.

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Tumoral Melanosis, Regressing Nevi, and Regressing Melanoma: Immunohistochemical Comparison of the Inflammatory Infiltrate

Eva George and Kiran Motaparthi

Department of Dermatology, University of Florida, Gainesville, FL.

Tumoral melanosis (TM) is characterized by aggregates of heavily pigmented melanophages, attributed to regressed melanocytic neoplasia. However, the absence of identifiable melanocytes prevents definitive association of TM with antecendent melanoma versus nevus. Anecdotal evidence correlates TM with regressed melanoma, although follow-up data from larger series is lacking. In the programmed cell death-1 (PD-1) pathway, upregulation of PD-L1, bound by the PD-1 receptor on cytotoxic T cells, dampens tumor directed immunity. Plasmacellular infiltrates have been described more often in association with regressing melanoma than with regressing nevi. In the largest series reported thus far, we characterize the inflammatory infiltrate of TM, regressing nevi, and regressing melanoma with an immunohistochemical panel (PD-1, PD-L1, CD138). When encountering TM, immunoprofiling of the inflammatory infiltrate may favor antecedent melanoma versus nevus.

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Cutaneous Blastic Plasmacytoid Dendritic Cell Neoplasm: Report of a Rare Entity

Michael Greas, MD, Tiannan Wang, MD, and Jun Wang, MD

Department of Pathology, Loma Linda University, Loma Linda, CA.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy. Occurs mainly in older adults with a median age of 66 and commonly presents as cutaneous lesions with or without bone marrow involvement and leukemic dissemination. Herein, we report a case of BPDCN in a 23-year-old male who presented with a non-tender brown anterior tibial lesion followed by back pain, fever, chills, night sweat, weight loss and pancytopenia. Skin punch biopsy showed defuse dermal infiltrate of medium to large-sized monotonous blastic cells with intact Grenz zone and no evidence of epidermotropism. Immunohistochemically the cells were diffusely positive for CD123, TCL-1, TdT and negative for CD3 and PAX5. CD56 and CD4 showed weak focal positivity. Although BPDCN was previously called “blastic NK-cell leukemia/lymphoma” or “Agranular CD4+ CD56 + hematodermic neoplasm/tumor” BPDCN is currently considered a clinically aggressive tumor derived from the precursors of plasmacytoid dendritic cells with high frequency of cutaneous (virtually 100%) and bone marrow involvement, belonging to myeloid neoplasm based on the newly published 2017 WHO classification.

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A Case of Adult Onset Cutaneous Disseminated Xanthogranuloma

Audrey Green, MD, George Lin, MD, PhD, and Allen Strickler, MD, PhD

Departments of Dermatology and Pathology, Geisinger Medical Center, Danville, PA.

Xanthogranulomatosis is classified as a non-Langerhans cell histiocytosis that most commonly affects children. When xanthogranulomas occur in adults they usually present as solitary lesions involving the eye. Cases of adult onset disseminated xanthogranuloma are exceedingly rare. A 43-year-old male presented to our dermatology clinic with a 7-year history of a pruritic rash that involved his trunk and extremities. On exam, several red to yellow dome shaped papules were noted on his back and arms. A biopsy was performed which revealed a dermal proliferation of variably sized histiocytes with palely eosinophilic cytoplasm and occasional multinucleated giant cells. A diagnosis of disseminated xanthogranuloma was established. The patient was found to be otherwise healthy, and work-up for an underlying malignancy has been negative to date. While disseminated xanthogranuloma is rare in adults, it is an important entity to consider in the differential diagnosis of xanthomatous diseases. Since a few cases have been linked to hematologic malignancies, continued surveillance is important. However, this entity lacks any visceral involvement and overall portends an excellent prognosis.

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Rare Spindles in the Dermis: Clear Cell Leiomyosarcoma and Menigioma-Like Tumor of the Skin

Bryan Edgar Guevara, MD,*,† Rajendra Singh, MD,† Matthew Goldberg, MD,† and Robert Phelps, MD†

*Southern Philippines Medical Center, Davao, Philippines; and †Mount Sinai School of Medicine, New York, NY.

Introduction: Spindle cell dermal lesions can be difficult to diagnose due to the heterogeneity, especially for dermatopathologists who are not exposed to soft tissue lesions. We present two rarely described spindle cell lesions.

Case 1: A 34-year old female presented with a rapidly growing polypoid nodule on the hip for a year. The lesion showed atypical spindle-shaped cells and clear cells with granular cytoplasm, pleomorphic nuclei, some with hyperchromasia and prominent nucleoli. Scattered mitosis were noted. The spindle cells were positive for caldesmon and focally for desmin and SMA whereas S-100, CD34 and HMB-45 were negative. Based on the immunohistochemical findings, a diagnosis of primary cutaneous clear cell leiomyosarcoma was made.

Case 2: An 35-yr old female presented with a nodule on his thigh. Her skin biopsy showed poorly circumscribed spindle cell proliferation in the dermis, which exhibited perivascular cuffing. The cells showed oval bland nuclei without atypia. Intervening stroma often exhibited clefting. The spindle cells show strong positivity with CD34 and were negative for S-100 and SMA. Differential diagnosis included meningioma-like tumor of the skin or dermal fibroma with perivascular arrangement.

Conclusions: We highlight two rarely described spindle-cell tumors that dermatopathologists can consider when diagnosing difficult spindle cell lesions.

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Acral Pseudolymphomatous Angiokeratoma of Children: (Apache): A Misnomer in Dermatopathology

Bryan Guevara, MD,*,† Nikki Vyas, MD,† Michelle Min, MD,† and Robert Phelps, MD†

*Southern Philippines Medical Center, Davao, Philippines; and †Icahn School of Medicine at Mount Sinai, NY.

Introduction: Acral pseudolymphomatous angiokeratoma of children (APACHE) is a rare benign cutaneous disease of unknown etiology. Paradoxically, there have been several reported cases occurring in adults and at non-acral sites. Here, we present a case of APACHE syndrome occurring in an adult that makes this diagnostically challenging.

Case Report: A 45-year old man presented with asymptomatic multiple erythematous papules primarily on the right leg for 3 years. Biopsy revealed dermal lymphohistiocytic infiltrate with plasma cells and multinucleated giant cell and vascular proliferation in the dermis. The infiltrate was CD30(−), CD4(++), CD8(++), CD7(++), iron(+). The infiltrate also showed scattered staining for CD68 and CD20. T-cell receptor gamma and beta gene rearrangement studies also showed a monoclonal or oligoclonal T cell population.

Conclusions: Our case illustrates how to work up a case of possible APACHE syndrome and also illustrates why “APACHE” is a misnomer. An alternate term has previously reported in the literature, “popular angiolymphoid hyperplasia,” and maybe more appropriate to use in adult cases of APACHE syndrome. Our case also explores the challenges and significance of interpreting clonality and pseudoclonality in such cases.

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Megalin Expression Decreases in Psoriatic Lesions

Tao Guo, MD,* Anna A. Brozyna, PhD,† and Andrzej T. Slominski, MD, PhD*,‡

*Departments of Dermatology, and Pathology and Laboratory Medicine, University of Alabama at Birmingham, Birmingham, AL; †Department of Tumor Pathology and Pathomorphology, Faculty of Health Sciences, Nicolaus Copernicus University Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland; and ‡Laboratory Service, VA Medical Center at Birmingham, Birmingham, AL.

Defects in vitamin D have recently been implicated in the pathogenesis of psoriasis. However, the underlying mechanism regarding downstream vitamin D pathway in psoriasis is yet to be understood. We hypothesize that megalin, a multiligand receptor known to mediate cellular uptake and trafficking of vitamin D, is playing an important role in the development of psoriasis. Using immunohistochemistry, we analyzed the megalin expression in epidermis of 11 psoriasis and 6 normal skin samples. In the epidermis of normal and psoriatic skins, megalin immunoreactivity shows a granular pattern with gradient staining intensity being the strongest in stratum granulosum and upper stratum spinosum layers. However, the megalin expression dramatically decreases in psoriatic skin lesions in comparison to normal skin. This pilot study provides evidence for the first time that megalin may be involved in pathogenesis of psoriasis.

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Neutrophilic Figurate Erythema of Infancy: A Rare Pediatric Disease

Sepehr Hamidi,* Elizabeth S. Bressler,*,† Neil S. Prose,† Kristen M. Paral,* and M. Angelica Selim*,†

Departments of *Pathology, and †Dermatology, Duke University, Durham, NC.

Reports of neutrophilic figurate erythema of infancy (NFEI) are very rare. We present the case of a 9-month-old female admitted with a skin rash of unclear etiology. The rash started on her face at the age of 2–3 months and gradually spread to her arms and legs. She had no constitutional symptoms, and her health and development were otherwise unremarkable since birth. This persistent skin eruption consisted of many ill-defined erythematous papules and annular plaques. A trial of topical steroids was unsuccessful. Histologic examination revealed perivascular neutrophils and eosinophils with abundant nuclear dust without signs of vasculitis. NFEI is a variant of annular erythema of infancy. It is characterized by annular erythematous plaques, occasionally with a polycyclic configuration. The main challenge is to differentiate this rare entity from other figurate erythemas associated with serious diseases such as neonatal lupus erythematosus. Absence of an underlying cause combined with the peculiar histology of dermal neutrophilic infiltrate with leukocytoclasia are the keys to diagnosis. Awareness of this disease may alleviate parents' concerns since reassurance and a watch-and-wait policy are the best approach.

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Primary Cutaneous Nodular Amyloid of the Feet

Paul M. Hoesly, MD and Jason C. Sluzevich, MD

Mayo Clinic, Jacksonville, FL.

A 58 year-old male presented with a one-year history of gradually enlarging, asymptomatic papules and plaques on the feet. Review of systems was negative. On physical examination, there was a discrete, red-brown, cerebriform plaque on the right sole. There were also several smaller, smooth, skin-colored, dome-shaped papules on both plantar feet, particularly near the inter-digital web spaces. A 4-mm punch biopsy revealed dense dermal deposition of eosinophilic material admixed with small collections of plasma cells. Congo red stain was positive, and CK903 immunostain was negative. Further immunostaining revealed a predominance of lambda light chain over kappa light chain, indicating a small local monotypic plasma cell population. Mass spectrometry confirmed the presence of AL (lambda)-type amyloid deposition. SPEP results were within normal limits, rendering a diagnosis of primary cutaneous nodular amyloidosis. (PCNA). PCNA is an uncommon disorder characterized by local deposition of light-chain immunoglobulin within the skin. It most commonly presents with infiltrative plaques or nodules localized to the head, trunk, and extremities. This case highlights a rare clinical presentation of PCNA occurring on the plantar feet and inter-digital web spaces. Long-term follow-up is recommended as 7%–50% of cases of nodular cutaneous amyloidosis have been reported to progress to systemic forms.

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Keratosis Pilaris Rubra Histologically Mimicking Lupus Erythematosus: A Diagnostic Pitfall

Anna-Marie Hosking, BS, Ashley Elsensohn, MD, Joy Makdisi, MD, Sergei Grando, MD, PhD, and Sebastien de Feraudy, MD, PhD

Department of Dermatology, University of California Irvine, Irvine, CA.

Keratosis pilaris (KP) is a benign cutaneous disorder characterized by folliculocentric hyperkeratotic papules most often occurring on the proximal extremities. Erythema is usually limited to perifollicular skin, but when keratosis pilaris presents on a background of confluent erythema, the term keratosis pilaris rubra (KPR) is used. The histological findings associated with KPR have not been well described in the literature. We present a case of a 14-year-old male with a 7-year history of erythema and follicular-based papules over his bilateral cheeks, consistent with KPR. Histological examination revealed abundant mucin, keratotic follicular plugging, and periadnexal lymphocytosis. To our knowledge, mucin deposition has never before been reported in a case of KP. Although non-specific, the presence of mucin raises concern for connective tissue diseases, including lupus erythematosus. Awareness of this histologic finding in KPR is important in order to avoid making an incorrect diagnosis of cutaneous lupus, which might trigger an extensive workup for systemic lupus as well as increased anxiety for the patient and family.

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Multinucleate Cell Angiohistiocytoma: A Rare Imitator

Mojgan Hosseinipour, DO,* Sonya Zarkhin, DO,† Ronald R. Brancaccio, MD,‡ and Cindy Hoffman, DO§

*St. Barnabas Hospital, Bronx, NY; †Larkin Community Hospital, Palm Springs, FL; ‡Skin Institute of NY, Brooklyn, NY; and §St. Barnabas Hospital, Bronx, NY.

We present a case of a 74-year-old woman with a persistent papular erythematous eruption of the left lower extremity, involving the knee, foreleg and anterior medial distal thigh, present for 6 months. A diagnosis of multinucleate cell angiohistocytoma was made based on histologic features observed in the upper to mid-dermis. The patient was started on triamcinolone acetonide 0.1% cream twice daily to the left proximal pretibial region with improvement after 2 weeks of treatment. Multinucleate cell angiohistiocytoma (MCAH) is a rare condition that typically presents as slowly growing, erythematous to violaceous papules and plaques most commonly on the lower extremities. Upon review of literature, there are fewer than 150 published reports of this condition. Despite this, MCAH is an important condition to consider as its cutaneous presentation mimics many disorders, including Kaposi's sarcoma, granuloma annulare and lichen planus. We present this case of MCAH to highlight an uncommon disease that is underreported and often misdiagnosed, and to stress the importance of differentiating MCAH from more serious cutaneous disease.

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Extra-Mammary Paget's Disease: A Case Report and Review of Immunohistochemical Stains

Monica Huynh, DO,* Nikki Vyas, MD,† Craig Austin, MD,‡ and Charles Gropper, MD*

*SBH Health Systems, Department of Dermatology, Bronx, NY; †Icahn School of Medicine at Mount Sinai; and ‡Craig Austin Dermatology, New York, NY.

Extra-mammary Paget's Disease (EMPD) is a rare form of intraepithelial adenocarcinoma. In 1889, Crocker et al was the first to recognize and report EMPD as a distinct entity from Paget's Disease. EMPD is morphologically and histologically identical to Paget's Disease of the nipple with the primary difference being the anatomic location. Most cases involve apocrine-rich areas with the vulva being the most common site; other common areas include perineal, scrotal, perianal, and penile skin. Typically it occurs in the fifth and sixth decade of life most often in Caucasian women. Due to the insidious progression of disease, the average time from symptom onset to accurate diagnosis is approximately 4 years. Clinical diagnosis is of utmost significance as 25% of cases are associated with an underlying in situ or invasive neoplasm, most likely an adnexal apocrine carcinoma. We present a case of a 79-year-old female with a 4-month history of a left inguinal erythematous macerated plaque refractory to topical antifungals and corticosteroids later to be diagnosed as EMPD. We will review the utilization of immunohistochemical staining to differentiate EMPD from other spindle-cell neoplasms and determine prognosis.

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Heterozygous A1AT-Associated Panniculitis: A Simple Approach to a Difficult Diagnosis

Joanna Jaros,* Iris Aronson,† Jeremiah Au,† Lorelei DiTommaso,† and M. Braniecki*

Departments of *Pathology, and †Dermatology, University of Illinois at Chicago, Chicago, IL.

Panniculitis is a rare complication of alpha-1-antitrypsin (A1AT) deficiency and is most commonly reported in the homozygous phenotype with concurrent liver and/or lung involvement. Histopathology is described as neutrophilic infiltrates involving fat lobules/septae associated with collagenolysis. We present a case of a 19-year-old woman with lower extremity panniculitis as a primary manifestation of heterozygous A1AT deficiency and discuss diagnostic histopathology. Our patient presented with an enlarging erythematous shin plaque that sometimes drained oily fluid. Her medical history is significant for a maternal aunt who expired from (A1AT) deficiency. She had low A1AT level of 99 mg/dl. Skin biopsy revealed subcutaneous fat with mixed septal-lobular panniculitis and fibrinolysis. One also saw a depletion of elastic fibers. This loss of elastic fibers in the fat septae along with fibrinolysis is helpful in making the diagnosis of (A1AT) deficiency-associated panniculitis. Our patient was then able to receive infusions of alpha-1-preinase inhibitor and has significantly improved. This case demonstrates the necessary recognition of elastic fiber depletion when diagnosing A1AT-associated panniculitis.

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Autoamputating Dermatofibrosarcoma Protruberans

Judith Jebastin, MD, Jason Pimentel, MD, and Kyle Perry, MD

Henry Ford Health System, Detroit, MI.

This case is a 31 year old healthy female who presented with a skin lesion of several years, slowly increasing in size that had spontaneously fallen off her back. Previously, an outside institution determined this was a keloid, but no biopsy was performed. On examination, there was a 2 × 2 cm circular wound with mild bleeding on her back with adjacent nodularity, but no surrounding erythema. The detached lesion was a 2 × 2 × 0.5 cm flesh colored cauliflower-form mass with a clean base. The clinical impression was dermatofibroma, keloid or melanoma among others. Microscopically, the detached portion was a CD34-positive dermal spindle cell proliferation with a fascicular and storiform pattern and a positive deep margin, consistent with dermatofibroma protuberans (DFSP). Due to the large size and indistinct clinical borders, Mohs micrographic surgery with three stages and a total of 51 sections was performed to ensure complete removal of the tumor. DFSP usually presents as a slow growing papule or nodule which can show necrosis, hemorrhage and accelerated growth, but autoamputation has not been described in the English literature.

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Immunohistochemical Characterization of Lichen Planopilaris and Central Centrifugal Cicatricial Alopecia

Christian Jordan, MD, PhD,* Cindi Chapman, MD,† Athanassios Kolivras, MD,‡ Janet Roberts, MD,§ Nathaniel Thompson, MPA,¶ and Curtis Thompson, MD†

*Department of Dermatology, University of Cincinnati, OH; †Oregon Health and Science University, Portland, OR; ‡Université libre de Bruxelles, Belgium; §Northwest Dermatology and Research Center, Portland, OR; and ¶Appuri, Seattle, WA.

Central centrifugal cicatricial alopecia (CCCA) remains a poorly defined histological entity, which many consider a clinical variant of lichen planopilaris (LPP). No histologic feature has been identified as unique to CCCA, making a definitive diagnosis difficult even for expert clinicians and dermatopathologists. This study aims to histologically and immunohistochemically compare CCCA and LPP using histologic and molecular markers. IHC was used to assess the nature of the inflammatory infiltrate (CD3, CD4, CD8, CD20, myeloperoxidase, CD68, CD123) and the presence of follicular bulge stem cells (CK15.) There was no difference between LPP and CCCA on histology or IHC. These data strongly support the view that CCCA is one of several clinical subtypes of LPP. Both entities are a primary lymphocytic scarring alopecia with identical histologic and immunohistochemical findings, demonstrating that a distinction between the two entities is only possible clinically.

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SMARCB1/INI1-Negative Tumor in a Hand of a 12-Year-Old Girl—An Unusual Presentation of an Epithelioid Malignant Peripheral Nerve Sheath Tumor

Yuna Kang, MD and Sarah Dry, MD

University of California Los Angeles, Los Angeles, CA.

SMARCB1/INI1-negative tumors represent a heterogeneous group of tumors, a large majority of which affects the pediatric population. We describe an unusual case of a 12-year-old girl with a prior history of atypical teratoid rhabdoid tumor (ATRT) of the brain, who presented with a 1 year history of a papule on the dorsal right hand. Clinically, pyogenic granuloma was suspected. The biopsy revealed a 3.5 mm well-circumscribed, unencapsulated dermal nodule protruding into the epidermis, composed of a storiform growth of markedly pleomorphic, mitotically active, spindle and epithelioid tumor cells. By immunohistochemistry, the tumor showed strong, diffuse expression of S100 and SOX10 and patchy expression of EMA. SMARCB1/INI1 and pankeratin were negative. These features were consistent with an epithelioid malignant peripheral nerve sheath tumor (MPNST), while arguing against a metastatic ATRT. Germline testing for SMARCB1 mutation was recommended given this unusual presentation of two INI1-negative tumors in this patient. To our knowledge, this is the first report of ATRT and epithelioid MPNST occurring in the same patient.

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Case Report: A CD4-Negatlve Variant of CD4+/CD56 + Hematodermic Neoplasm

Mohammad S. Khan, DO,* Michael A. Lewis, MD,*,† Hillary Mandel,† and Philip Scumpia, MD†,‡

*Cedars-Sinai, Los Angeles, CA; †WLA VA Hospital; and ‡UCLA Dermatology.

Hematodermic neoplasm (HN) is a rare and clinically aggressive entity with a high risk of cutaneous involvement and leukemic dissemination. Immunophenotypically, HNs are classically positive for CD4 and CD56 and therefore cases that lack their expression represent a diagnostic problem. Characterization of such neoplasms becomes necessary to avoid confusion. Herein, we report a case of a 73 year-old man who presented with purpuric lesions of the shoulder, chest, and forehead, which rapidly evolved into violaceous plaques. Biopsy of a forehead lesion revealed a CD4, CD56+ and CD 123 + hematodermic neoplasm with bone marrow involvement. Tumor cells strongly expressed Bcl-2 and Bcl-6, antigens commonly expressed in CD4+ HNs. In particular, BcI-2, recently shown to regulate survival in plasmacytic dendritic cells and proposed as a novel therapeutic target in CD4+ HNs may be an exploitable target in CD4 HNs given our findings. Due to their aggressive nature, recognition and characterization of this variant is important for early diagnosis, avoidance of diagnostic pitfalls and proper management.

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Coexistent Plantar Poroma and Papillary Eccrine Adenoma of the Ankle

Aleksandar Krbanjevic,* Daniela Atencio,† Matthew Ranzer,† and Marylee Braniecki*

Departments of *Pathology, and †Surgery, University of Illinois at Chicago, Chicago, IL.

Papillary eccrine adenoma (PEA) is a rare benign skin tumor arising from eccrine sweat glands. PEA is most commonly seen on the extremities. It is even more rarely associated with other lesions of adnexal origin. We herein report a case of a PEA and eccrine poroma occurring on the same lower extremity. A 31-year-old female presented with two separate, slowly growing masses localized on the right plantar surface (1.5 × 1.2 cm) and on the right medial ankle (2.3 × 1.1 cm). The painful, exophytic mass on the plantar foot prompted the patient to seek medical help. Patient had no significant medical history or family syndromes. Both plantar foot and ankle masses were surgically resected. The plantar lesion revealed characteristic histology of an eccrine poroma. The ankle lesion microscopically demonstrated dilated eccrine ducts with intraluminal projections and microcystic glandular proliferations consistent with a PEA. We share this rare case of PEA and its unusual coexistent occurrence of another eccrine tumor on the same lower extremity.

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Undifferentiated Pleomorphic Sarcoma Arising from a Radiated Squamous Cell Carcinoma

Ashish Kurundkar, MD, MSPH, PhD, Paul Boothe, MD, Wayne Tyus, David Ullman, MD, Chirag R. Patel, MD, Todd Stevens, MD, and Peter Pavlidakey, MD

Departments of Pathology and Dermatology, University of Alabama at Birmingham, Birmingham, AL.

Clinical History: An 85-year-old male with a history of squamous cell carcinoma of the scalp status-post resection with concurrent radiation therapy presented with multiple scalp lesions. The most pronounced lesion was a 2.5 cm midline mass. Head CT showed enhancing lesions in the soft tissue and calvarium. Biopsy of the midline lesion was histologically consistent with undifferentiated pleomorphic sarcoma (UPS) and was negative for immunohistochemical stains: CD34, pan-cytokeratin, ERG, p63, S100, SMA, and Sox10. This midline lesion was transected at the base of the biopsy and depth of invasion could not be assessed. The differential diagnosis at that time included UPS and atypical fibroxanthoma (AFX).

Discussion: While the initial biopsy demonstrated features of UPS, without clinical context, these findings could be mistaken for AFX. This case highlights the need for radiographic and clinical correlation to separate two entities that are histologically similar but have drastically different prognoses.

The authors have no conflicts of interest related to this abstract.

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Panniculitis Resembling Sclerosing Lipogranuloma in Patient Taking Pazopanib

Michael D. Lehrer, Mark R. Pittelkow, and David J. DiCaudo

Mayo Clinic Arizona, Scottsdale, AZ.

Background: Pazopanib is a third generation oral multikinase angiogenesis inhibitor (MKI) approved for metastatic renal cell carcinoma (RCC). Panniculitis has been reported amongst kinase inhibitors (KI), most notably BRAF inhibitors; however panniculitis has not been reported with pazopanib. Sclerosing lipogranuloma is rare, and most commonly seen as a foreign body reaction.

Report of Case: A 68 year old female with metastatic RCC presented with a 1.5 years history of tender atrophic plaques on her hip, buttocks, breast, and lower back. She had been treated with pazopanib for 4.5 years. An incisional biopsy demonstrated prominent fatty microcysts with a densely sclerotic background. Lipophages were identified surrounding many microcysts. Polarization revealed no retractile bodies.

Discussion: Panniculitis has been reported with BRAF inhibitors, and rarely amongst other MKI. The histologic characteristics of panniculitis amongst KI are highly variable. The scattered areas of clinically apparent panniculitis with close temporal relation would argue against local injection as a cause of her panniculitis. Panniculitis may occur in association with pazopanib, and may present with odd histologic characteristics including those resembling sclerosing lipogranuloma.

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Pseudoangiosarcomatous Squamous Cell Carcinoma: A Rare Mimic of Cutaneous Angiosarcoma

Christine Lee, MD, Mark Lincoln, MD, Chandra Smart, MD, Peter Sarantopoulos, MD, and Scott Binder, MD

UCLA Department of Pathology and Laboratory Medicine.

Pseudoangiosarcomatous squamous cell carcinoma is a rare, aggressive variant of SCC with a poor prognosis and histologic appearance that mimics angiosarcoma. We report a case of this entity in an older, post-transplant patient with numerous recurrent squamous cell carcinomas. Histologically, this tumor has an acantholytic pattern with pseudovascular channels lined by atypical, neoplastic keratinocytes. An immunophenotype that is positive for squamous markers and negative for endothelial markers helps to confirm the diagnosis. It is important for pathologists to recognize and report this variant of squamous cell carcinoma to clinicians as this tumor is associated with high rates of mortality, morbidity, and metastasis. Clinical factors, such as immune compromise, can further portend a worse prognosis and emphasize the importance of an accurate and informative diagnosis in regards to providing prompt and often radical treatment.

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Psoriasiform Sarcoidosis With Transepidermal Elimination of Granuloma

Mario Mitkov, MD, Jason Sluzevich, MD, and Mark Cappel, MD

Mayo Clinic Department of Dermatology, Jacksonville, FL.

A 52 year-old African American man with known pulmonary sarcoid presented with a 20 years history of progressive verrucous and psoriasiform plaques over his elbows, knees, palms, and face. Multiple punch biopsies revealed pseudoepitheliomatous hyperplasia, diffuse pan-dermal sarcoidal granulomatous inflammation abutting the epidermis along with intraepidermal granulomas. Grocott's methenamine silver (GMS), Acid fast bacillus (AFB) stains, and polarization were all negative. Historically known as “the great mimicker,” sarcoid clinically resembles numerous dermatologic conditions including psoriasis in less than 1% of cases. This case is notable for its clinical and histologic appearance, which demostrates granulomas within the epidermis, a phenomenon that has only been described once before. It is postulated that the Th1 and Th17 cytokines that drive the pathogenesis of sarcoid also induce psoriasiform epidermal hyperplasia. Likewise, it has been proposed that TNF alpha blockade is an effective approach to the treatment of this disease entity.

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Labial Spindle Cell Lipoma

Shanice Mckenzie, G. Peter Sarantopoulos, Scott Binder, Chandra Smart, and William R. Munday

Department of Pathology, David Geffen School of Medicine at the University of California, Los Angeles, CA.

Background: Spindle cell lipoma is a rare tumor that typically presents on the back and shoulders of elderly males. This creates diagnostic difficulty when atypical presentations occur, such as those occurring in female patients, in whom this entity is uncommon, and especially when the lesion arises at unusual anatomic sites.

Methods: We report a case of labial spindle cell lipoma occurring in a 39-year-old female.

Results: Histologic evaluation demonstrated an infiltrative proliferation of spindle cells arranged in short fascicles and admixed amongst mature adipose tissue. Immunohistochemical analysis revealed spindle cell positivity for CD34 and loss of Rb protein expression.

Conclusions: We present the third reported case of labial spindle cell lipoma, and the first, to our knowledge, to arise in a patient of reproductive age. Given its infiltrative growth pattern, if not considered in the differential diagnosis, labial spindle cell lipoma may be misdiagnosed as one of the more common and locally aggressive CD34 positive spindle cell tumors native to the female genital tract.

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Squamous Cell Carcinoma of the Nail Matrix—an Indolent Presentation of a Rare Entity

David J. Myers, MD, James R. Neiner, MD, and Kevin J. Krauland, MD

San Antonio Uniformed Services Health Education Consortium, San Antonio, TX.

A 67 year-old male with history of multiple basal cell carcinomas of the cheek reported changes in the left thumb nail at his annual full body skin exam. The nail had first shown dystrophic changes at the age of 20, but recently the band of dystrophic looking nail had expanded. Punch biopsy of the nail matrix was performed. Histology demonstrated nail matrix epithelium with areas of full-thickness cytologic atypia and superficial dermal invasion. Immunohistochemical staining highlighted areas of elevated Ki-67 labeling of lesional keratinocytes as well as scattered P53 and P16 positive lesional cells in the epithelium and at both lateral margins. These findings are characteristic of superficial nail unit squamous cell carcinoma (SCC). Subsequent Mohs surgery was performed which was negative for SCC intra-operatively, but permanent section demonstrated margin positive SCC in situ. Re-excision with Mohs successfully excised the lesion. This case demonstrates that nail matrix SCC can have an indolent presentation with nonspecific clinical findings.

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A Study of a Clinical Case With Pityriasis Lichenoides

Liudmyla Naumova,* Lev Prystupiuk,* and Marianna Naumova†

*Bogomolets National Medical University, Kyiv, Ukraine; and †Shupyk National Medical Academy, Kyiv, Ukraine.

Pityriasis lichenoides is an uncommon rash of unknown etiology. It is could manifests from acute papular lesions with pseudovesicles and central necrosis, pityriasis lichenoides et varioliformis acuta (PLEVA) or a small, scaling, benign-appearing papules, pityriasis lichenoides chronica (PLC). We present a case of 16-year old male with a history of spontaneous rash on trunk and upper extremities. The lesion was described by small scale symmetrically erythematous–to–reddish brown papules. Dermoscopic features reported linear irregular vessels. Both clinical and lab exams showed normality in the function of his other organs. On this basis, guttate psoriasis was clinically diagnosed. A skin biopsy was performed and the result was consistent with superficial dermal infiltrate, focal parakeratosis, preservation of the granular layer, and focal disappearance of the dermal–epidermal interface. In the upper dermis noticed were lichenoid lymphohistiocytic infiltrate. This histology results led to the diagnosis of PLC. Our conclusion that a biopsy is necessary for proper diagnosis and for good therapeutic management especially in case of rare skin disorders.

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Signet Ring Squamous Cell Carcinoma In Situ: A Previously Unreported Entity and Diagnostic Pitfall

Alexander Nobori, MD and Peter Sarantopoulos, MD

Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA.

Signet-ring morphology is most commonly associated with gastric or breast adenocarcinoma and in the context of skin pathology is frequently attributed to metastatic disease. Cutaneous squamous cell carcinoma (cSCC) with signet-cell morphology was first described in 1989, and 14 cases of signet-cell cSCC have been reported to date. We present the first known case of cSCC in situ/Bowen's disease with signet ring cell morphology. The patient is a 93 year-old woman with 2 right lower leg skin lesions. Histologic sections of both biopsies demonstrated ulcerated skin with full thickness atypia and prominent signet-ring morphology with negative mucin staining within the signet-ring cells. Immunohisto-chemical stains showed positivity with cytokeratin 5/6 and p63, suggesting primary epidermal origin. BerEP4, CD10, and S-100 stains were negative, excluding clear cell melanoma and clear cell basal cell carcinoma. We recommended complete excision to evaluate margin status. Given that this entity's main differential diagnosis, metastatic adenocarcinoma, requires an alternative management strategy, we highlight the importance of identifying this unusual presentation of cSCC in situ.

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Adenodermatofibroma on the Back

Chika Ohata, Ikko Muto, Fumi Kuwahara, Takako Shintani, Hiroshi Saruta, and Takekuni Nakama

Department of Dermatology, Kurume University School of Medicine, Kurume, Fukuoka, Japan.

Adenodermatofibroma is a type of dermatofibroma, characterized by the presence of entrapped dilated apocrine glands. To date, only 5 cases of adenodermatofibroma have been reported. A 67-year-old female presented with an itchy and slightly painful nodule on the back, which appeared 10 years before and enlarged gradually. Physical examination revealed a brown nodule, 3 cm × 4 cm in size, with a purplish center, on the left lower back. The excision of the nodule revealed fibroblastic and histiocytic cell proliferation with dilated apocrine glandular structures in the dermis and subcutis. Overlying epidermis was thickened, and keloidal collagen was present at the periphery of the lesion. The lesion had many blood vessels, some of which were dilated, and some foci showed hemorrhage. The constituent cells of the lesion were positive for Factor XIIIa and negative for CD34. The patient was diagnosed with adenodermatofibroma. No recurrence reported within 6 months after the excision. Although hemosiderotic changes were not observed in 2 cases reported by Santos-Briz, et al, our case and the previous 3 cases exhibited hemosiderotic changes. Additional cases will elucidate whether hemosiderotic changes are the major characteristics of adenodermatofibroma.

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Gouty Panniculitis: A Case Report

Oluwakemi Onajin, MD, Nataly Portilla Maya, MD, Katarina Kesty, MD, and Omar P. Sangüeza, MD

Department of Pathology and Dermatology, Wake Forest School of Medicine, Winston-Salem, NC.

Gouty panniculitis is a rare cutaneous manifestation of gout characterized by the deposition of monosodium urate crystals in the subcutaneous tissue. To our knowledge, less than 15 cases have been reported in the literature. We present a case of gouty panniculitis mimicking erythema nodosum clinically. A 49-year-old man presented with a 10-year history of asymptomatic, widespread, hyperpigmented, and indurated nodules and plaques involving the bilateral lower extremities. Skin biopsy revealed extensive palisading granulomatous inflammation surrounding amorphous pink to gray feathery materials within the deep dermis and subcutaneous tissue. The patient had a long-standing history of gout and was being treated with Febuxostat. We present this interesting case to highlight a rare cutaneous manifestation of gout. Gouty panniculitis should be considered in patients who present with nonspecific subcutaneous nodules in the setting of hyperuricemia and gout.

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Sclerosing Nevi With Pseudomelanomatous Features: An Emerging Melanoma Mimic

Brandy R. Pownell, MD and Ali D. Jassim, MD, PhD

University of South Dakota Sanford School of Medicine, Sioux Falls, SD.

A variety of pigmented lesions may demonstrate dermal fibrosis associated with melanomatous features. A distinct histopathologic subset of sclerosing nevi with pseudomelanomatous features has recently been described, characterized by a trizonal pattern including a junctional melanocytic component with overlying pagetoid spread, pronounced dermal fibrosis containing atypical melanocytic nests, and a residual mature dermal component. These sclerosing nevi may be confused with a regressed melanoma. To address this challenging differential diagnosis, we present a recent series of four cases with the described characteristics and no evidence of cytologic atypia or mitoses. No metastasis was present over an average follow-up of one year. Sclerosing nevi with pseudomelanomatous features present unique diagnostic difficulties, and though initially thought to be fairly uncommon, a significant number of these lesions have been recently diagnosed at our facility, which were likely historically misinterpreted as malignant. Although they demonstrate a variety of melanomatous features, they have not been found to exhibit malignant clinical behavior, and their recognition is paramount to avoid over-diagnosis as melanoma.

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A Rare Collision Tumor Involving 4 Diagnostic Entities

Brandy R. Pownell, MD and Ali D. Jassim, MD, PhD

University of South Dakota Sanford School of Medicine, Sioux Falls, SD.

A collision tumor is defined as two or more neoplasms, benign or malignant, which arise within a single lesion. The entities may blend histologically, but more often are found adjacent to one another. We present a case of a 73 year old male with a 7 mm pink papule on the left temple. Microscopic examination revealed four distinct lesions within the biopsy. At a site of previous biopsy, angular nests of basaloid cells with little cytoplasm and hyperchromatic nuclei within a myxoid stroma with stromal clefting were identified. In addition, dermal nests of benign melanocytes, dermal clusters of small ducts surrounded by epithelium with comma-shaped extensions, and a dermal tumor with dilated glandular spaces containing papillary projections into the lumina are all distinctly noted. Therefore, the diagnostic entities within the biopsy include an infiltrative basal cell carcinoma, a dermal nevus, an eccrine syringoma, and a papillary eccrine adenoma. Collision lesions containing three entities are rare, and to our knowledge, no collision tumors containing four entities have yet been described.

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Potential Pitfalls of Anaplastic Large Cell Lymphoma Mimicking an Abscess

Ali Rashidbaigi,*,† Alicia Goldenberg,*,† Christopher Caroway,*,† and Abraham Loo*,†

*RWJ-Barnabas Health Medical Center, Livingston, NJ; and †Monmouth Medical Center, Long Branch, NJ.

We present 2 cases of anaplastic large cell lymphoma (ALCL) mimicking an abscess in order to review their clinical presentation and pathogenesis, and to avoid a clinical misdiagnosis that may lead to a delayed diagnosis and worse outcome. Patient A is a 51 year-old female who presented with a right axillary abscess, which was incised and drained twice without biopsy. The patient was given antibiotics, but the mass increased in size. A subsequent excisional biopsy demonstrated ALCL, ALK (anaplastic lymphoma kinase) negative with marked overlying pseudoepitheliomatous hyperplasia. Patient B is a 57 year-old male who presented with right groin erythema. The patient had multiple admissions for suspicion of cellulitis/possible developing abscess and treated empirically with antibiotics. Incision and drainage and two nondiagnostic biopsies were performed. The patient was subsequently readmitted for an excisional biopsy, which demonstrated ALCL, ALK positive. Adequate biopsies should be performed in order to facilitate an accurate and timely diagnosis. An accurate diagnosis is essential given the different prognoses of ALCL, ALK positive; ALCL, ALK negative, and C-ALCL. We present these cases in order to prevent delayed treatment, which may result in increased morbidity and mortality.

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Cutaneous Metastasis of Carcinoma Disguised Clinically as a Vascular Neoplasm: A Diagnostic Review of Cutaneous Metastatic Breast Carcinoma

Ali Rashidbaigi,*,† Michael Williams,† Jonhan Ho,†,‡ Ramsay S. Farah,† and Joyce B. Farah†

*RWJ-Barnabas Health Medical Center, Livingston, NJ; †SUNY Upstate Medical Center, Syracuse, NY; and ‡University of Pittsburgh Medical Center, Pittsburgh, PA.

Metastatic lesions to the skin can present diagnostic dilemmas even when there is a known history of cancer. The incidence of cutaneous metastasis from all carcinomas is rare with breast cancer being the most common tumor to metastasize to the skin. Cutaneous metastases of breast carcinomas can present in a variety of ways clinically as nodules, plaques, carcinoma erysipeloides, and vascular neoplasms. Importantly, cutaneous metastasis can present as a great masquerader of underlying disease. We present a case of metastatic carcinoma to the patient's chest presenting clinically as a vascular neoplasm. We review the literature and present how the clinical history, morphology, immunohistochemistry, and molecular studies can guide us in suspected cases of cutaneous metastasis from the breast. Clinical and morphological presentations can create quandaries in evaluation, therefore, thorough dermatopathological evaluation is crucial to identifying the nature of the lesion.

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Histiocytic Angiosarcoma- Rare Morphology You Do Not Want to Miss

Stephanie L. Donaldson, BS,* Mohammed Rigi, MD,* and Peter G. Pavlidakey, MD*

*University of Alabama at Birmingham, Birmingham, AL.

Cutaneous angiosarcoma is an aggressive vascular neoplasm characterized histologically by dilated, anastomosing vascular structures with ill-defined borders. If you are fortunate, malignant endothelial cells are present. Varying histologic appearances have been reported including epithelioid, clear-cell, foam-cell, among others. This case presented to our consult service as a cutaneous lesion on the right shoulder of a 76-year-old male. Histologically the surface had somewhat pleiomorphic cells with a more granular epithelioid appearance. The working impression was that of an unusual Langerhans cell proliferation. To phenotype the cells a large panel of stains were performed and are as follows: negative for S100, Sox 10, CD30, CD20, CD3, CD45, pancytokeratin, p40, CD1a, CD99, CD14 and smooth muscle actin; positive for CD31, CD68 and ERG. CD163 highlights occasional cells. Given these findings, the lesion was most consistent with angiosarcoma. Splenic angiosarcomas have been noted to have some histiocytic differentiation. However, histiocytic differentiation in cutaneous lesions has yet to be reported in the medical literature to this date; thus, we report the first case of this rare entity.

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Leukemia Cutis in an Infant With Platelet-Derived Growth Factor Receptor Mutation

Mohammed Rigi, MD,* Casey Wang, MD,† Fady Mikhail, MD, PhD,‡ and Peter Pavlidakey, MD†

Departments of *Pathology, †Dermatology, and ‡Genetics, University of Alabama at Birmingham, Birmingham, AL.

Platelet-derived growth factor receptor-β translocations represent an important group of cytogenetic aberrations in both adult and pediatric hematologic malignancies. There has been identification of over 30 PDGFβR translocations resulting in fusion proteins. We report an atypical case of leukemia cutis in an infant with a t(1; 5) (q21; q33) translocation who presented with proptosis, nasal turbinate hypertrophy, and rash. Bone marrow biopsy showed a dysplastic monocytic population. Fluorescence in situ hybridization identified two related abnormal clones, both harboring balanced translocations t(1; 5) (q21; q33) that disrupt the platelet-derived growth factor receptor beta (PDGFβR) gene. Subsequent gene sequencing studies identified a TPM3-PDGFβR fusion protein.

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Dermatomyositis: A Complication that Arises from an Untreated Carcinoma and Correlation With Myositis-Specific Antibodies

Erin Roberts, MD,* Alina G. Bridges, DO,* and Julio C. Sartori Valinotti, MD*

*Mayo Clinic, Department of Dermatology, Rochester, MN.

A 58-year-old female presented to dermatology for a worsening, erythematous rash on the torso. Past medical history was significant for invasive ductal breast carcinoma diagnosed 6 months prior. At the time of evaluation, chemotherapy had not been initiated as she investigated alternative and complementary medical treatments. She presented with severe fatigue, muscle weakness and a worsening, pruritic, erythematous-to-violaceous dermatosis on her chest, back, and extremities. A skin biopsy showed vacuolar interface dermatitis. Direct immunofluorescence showed a strong shaggy basement membrane zone deposition with fibrinogen and scattered and clumped cytoids with IgM, IgA, and C3 typical for a lichenoid tissue reaction. Laboratory evaluation revealed elevated creatine kinase, aldolase, and anti-p155/140 antibodies. The clinical presentation and histopathologic findings were most consistent with malignancy-associated DM. Several studies have noted a relationship between myositis specific antibodies, specifically anti-p155, anti-p155/140, and anti-NPX-2, and malignancy associated DM. This case highlights the complications that arise from untreated or neglected carcinomas and reminds clinicians of the importance of clinicopathological correlation.

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Juvenile Temporal Arteritis

Bethany Rohr, MD and George Lin, MD, PhD

Departments of Dermatology and Dermatopathology, Geisinger Health Systems, Danville, PA.

Background: Juvenile temporal arteritis (JTA) is rare form of arterial inflammation with unknown etiology.

Case Description: A 21-year-old male presented for excision of a 7 mm firm, mobile subcutaneous mass over the left forehead. Histopathological evaluation revealed a muscular artery with marked intimal proliferation, inflammation of the vessel wall with lymphocytes and numerous eosinophils, and associated with endothelial hyperplasia and neovascularization that extended into perivascular tissue. An elastic stain showed disruption of the internal elastic lamina.

Discussion: Juvenile temporal arteritis is a rare entity manifested most often by a unilateral asymptomatic temporal nodule in children or adults less than 40 year old. JTA lacks systemic manifestations aside from an occasional peripheral eosinophilia. On histopathology, a lymphoeosinophilic and non-giant cell granulomatous infiltrate involves and surrounds a muscular artery with intimal hyperplasia and disruption of the internal elastic lamina. Additional findings include endothelial hyperplasia and possible thrombosis, neovascularization, and microaneurysmal disruption of the artery. Excision is curative.

Conclusions: We present a case of juvenile temporal arteritis, which is distinguished from other vasculitides by clinical, laboratory, and histological evaluation.

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Meta-Analysis Reveals Role of Inflammatory and Hyperproliferation Pathways in the Pathogenesis of Actinic Keratosis

Laraib Z. Safeer,* Jihad Aljabban,† Maryam Panahiazar,‡ Isaac Neuhaus,§ and Dexter Hadley‡

*Baylor College of Medicine, Houston, TX; †Ohio State University College of Medicine, Columbus, OH; ‡Institute for Computational Health Sciences, University of California, San Francisco, CA; and §Department of Dermatology, University of California San Francisco, CA.

Objective: Define the pathogenesis of actinic keratosis using crowd-sourced meta-analysis.

Methods: We analyzed 30 skin samples of actinic keratosis against healthy controls using our STARGEO platform. We then analyzed the signature in IPA Ingenuity.

Results: From skin analysis, we found IL-17A in psoriasis and granulocyte and agranulocyte adhesion and diapedesis as top canonical pathways. OSM (part of the IL-6 cytokine family) was the top upstream regulator. We noted upregulation of hyperproliferation genes SERPINB3/B4 (serpin peptidase inhibitors) and S100A8/A9 (upregulated in cutaneous squamous cell carcinoma and other epithelial malignancies). Additionally, we noted upregulated of inflammatory peptides DEFB4A/DEFB4B defensins, and of keratin 6A/6B.

Conclusions: Our analysis emphasized the role of hyperproliferation and IL-17A mediated inflammation in the pathogenesis of actinic keratosis.

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Meta-Analysis Illustrates Role of Interferon and T Helper Cell Signaling in Sjogren's Syndrome

Laraib Z. Safeer,* Jihad Aljabban,† Maryam Panahiazar,‡ Isaac Neuhaus,§ and Dexter Hadley‡

*Baylor College of Medicine, Houston, TX; †Ohio State University College of Medicine, Columbus, OH; ‡Institute for Computational Health Sciences, University of California, San Francisco, CA; and §Department of Dermatology, University of California San Francisco, CA.

Objective: Define pathogenesis of Sjogren's syndrome using crowd-sourced meta-analysis.

Methods: We analyzed 50 salivary glands and 282 blood samples from SS patients against healthy controls using our STARGEO platform. We then analyzed the signature in IPA Ingenuity.

Results: Salivary gland analysis showed iCOS-iCOSL and CD28 signaling in T helper cells as top canonical pathways. Interferonα and γ were top upstream regulators in both salivary glands and blood. We noted upregulation of T cell chemoattractants (CXCL9, 11, 13), B cell markers (CD20, PAX5), and risk alleles (HLA-DQA1). Blood analysis showed IFN and pattern recognition receptor as top canonical pathways. We observed upregulation of IFN-inducible genes such as IF127, IF144, and RSAD2 and of the hematopoietic oncoprotein ETV7.

Conclusions: Our analysis emphasized the role of interferon signaling and T helper activation in SS pathogenesis.

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An Ecchymotic Nodule on the Scalp of an Elderly Male Mimicking Angiosarcoma

Jasmine Saleh* and Ben J. Friedman†

*Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI; and †Henry Ford Health System, Departments of Dermatology and Pathology, Detroit, MI.

A 79 year-old male with a history of non-melanoma skin cancer and sun-damaged skin presented for a follow up skin check. On examination, an ecchymotic nodule was identified on his left frontal scalp, which was not present in a clinical photograph taken exactly 2 years prior to the current visit. The patient denied any preceding trauma or associated tenderness. A shave biopsy revealed mitotically active, atypical epithelioid and pleomorphic-appearing multinucleated cells dissecting between collagen bundles in the dermis with prominent associated erythrocyte extravasation. A background of solar elastosis was also observed. These microscopic findings alone combined with the clinical presentation raised concern for angiosarcoma. However, immunohistochemical stains for vascular markers (ERG, CD31, and CD34) failed to highlight the atypical cells. Additional stains were performed including S100, HMWK, Desmin, and SMA which were negative. A CD68 stain revealed scattered positivity. Taken together, these findings were most consistent with the rare variant of atypical fibroxanthoma, known as the pseudoangiomatoid-type. A review of this entity will be presented.

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Perianal Extramammary Paget's Disease With Basal Cell Carcinoma-Like Changes

Maryam Sayah, MD,* Shelly Stepenaskie, MD,* Joshua Hanson, MD,* Heloisa Soares, MD,† and Hillary Elwood, MD*

*Department of Pathology, University of New Mexico School of Medicine; and †Division of Hematology-Oncology, University of New Mexico School of Medicine.

Case: A 92-year-old male presented with a circumferential plaque-like mass extending 3 cm from the anus. Initial biopsy demonstrated a nodular basaloid carcinoma with mucinous stroma and peripheral palisading that had been diagnosed as a basal cell carcinoma at an outside institution. However, the tumor also has admixed atypical pagetoid mucinous cells. Additional biopsy at our institution revealed Fibroepithelioma of Pinkus-like epidermal changes along with numerous admixed atypical pagetoid cells. Immunohistochemical stains reveal that the atypical pagetoid cells in both biopsies are positive for CDX2, CK20, CAM 5.2 and negative for CK7 and SATB2, compatible with extramammary Paget's disease and concerning for colorectal primary.

Conclusions: Fibroepithelioma-like changes have been described in the literature as a rare phenomenon associated with anogenital Paget's disease. This case demonstrates extramammary Paget's with both fibroepithelioma-like changes as well as changes resembling a nodular basal cell carcinoma, the latter has not been well-described in the literature. This case highlights the challenge in making the diagnosis on limited biopsy material.

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Diffuse Large B-Cell Lymphoma Mimicking Panniculitis

Rosalind F. Sharain, MD,* Brian J. King, MD,† Ellen D. McPhail, MD,* and Alina G. Bridges, DO*,†

Departments of *Laboratory Medicine and Pathology, and †Dermatology, Mayo Clinic, Rochester, MN.

A 79-year-old woman presented with a 3-week history of numerous rapidly progressive subcutaneous nodules on the torso, buttocks, and lower extremities. The nodules were skin-colored to slightly erythematous, nonmobile, indurated, and tender, having an appearance similar to erythema nodosum. She denied systemic symptoms, however, initial laboratory results unexpectedly revealed new pancytopenia, acute kidney injury, and elevated liver enzymes. A CT scan demonstrated multiple scattered subcutaneous masses along with a lobulated soft tissue mass within the omentum, concerning for malignancy. A deep punch biopsy confirmed diffuse large B-cell lymphoma (DLBCL) involving the subcutis. The differential diagnosis of subcutaneous nodules includes inflammatory and infectious panniculitides, a connective tissue disease, morphea or scleroderma, primary subcutaneous neoplasms, and secondary involvement by an underlying malignancy. DLBCL very rarely presents as subcutaneous nodules. Herein, we emphasize the possibility of DLBCL in the setting of a panniculitis-like presentation and encourage clinicians to maintain a low threshold for biopsy.

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A Unique Case of Combined Keloidal and Myxoid Dermatofibroma

Mohammad Shokouh-Amiri, MD and Marylee Braniecki, MD

Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, IL.

Dermatofibroma (DF) is one of the most common benign fibrous histiocytic cutaneous tumors. However, there are several unusual variants of DF which can exhibit different cellular and stromal compositions as well as growth patterns. Most of the combined dermatofibroma that have two variants are found more commonly in middle-aged female patients, and are primarily located in the lower extremities, followed by the upper extremities. A skin punch biopsy taken from the upper torso in a 31-year old male patient showed a dermatofibroma with two coexistent keloidal and myxoid variants in a single DF lesion. We, herein discuss a rare combination of variants that can occur in DF. Recognition and familiarity with these benign variants of DF may assist to avoid an over interpretation of these unusual benign findings.

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Mixed Apocrine Tumor of the Skin

Anastasia Sorokina,* Barry Ladizinski,† Shilpa Mehta,† Sook Hwang,† and Marylee Braniecki*

*Department of Pathology, University of Illinois Hospital at Chicago, Chicago, IL; and †Department of Dermatology, John H. Stroger Cook County.

A mixed apocrine tumor (MAT) is a benign neoplasm, consisting of epithelial, myoepithelial and mesenchymal components. Cutaneous mixed tumors are considered to be analogous to the pleomorphic adenoma of the salivary gland. We present a case of MAT in a 47 year-old man who developed a solitary nodule on the right nasal sidewall two years ago. It had slowly grown in size and was painless. On physical exam the mass was firm and non-tender with overlying normal appearing skin. Clinical differential diagnosis included basal cell carcinoma, sebaceous adenoma/carcinoma and Merkel cell carcinoma. Skin shave biopsy revealed a well-circumscribed dermal mass consisting of interconnecting epithelial islands with tubular-cystic ducts with foci of papillation and apocrine snouting. Other epithelial areas showed follicular differentiation. The surrounding mesenchyma demonstrated fibromyxoid changes. AMT has been termed “mixed tumor of the folliculosebaceous–apocrine complex. We share this case of AMT demonstrating the spectrum of divergent differentiation which can lead to diagnostic pitfalls.

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Primary Varicella Presenting With Coexistent Features of Pleva

Kayla St. Claire,* Divya Sachdev,† David Reid,† and Marylee Braniecki*

*Department of Pathology, University of Illinois at Chicago, Chicago, IL; and †Department of Dermatology, John H. Stroger Cook County.

Pityriasis lichenoides et varioliformis acuta (PLEVA) is a cutaneous inflammatory disorder that typically affects children and young adults. PLEVA commonly presents as an acute eruption of multiple hemorrhagic papules with eventual necrosis, ulceration and crusting. Although the pathogenesis is unknown, it is postulated that PLEVA represents a hypersensitivity reaction to infectious agents. We describe a case of varicella-associated PLEVA in a 27-year-old male who presented with fever and a 2-day history of rash. He is a Mexican immigrant with an unclear history of prior chickenpox exposure. Skin examination revealed diffuse hemorrhagic vesiculopustules in different stages of healing. Skin biopsy showed features of PLEVA. Distinct herpetic viral cytopathy was not appreciated. However, varicella-zoster virus (VZV) was detected by PCR. The patient had an elevated IgM titer to varicella, and no detected IgG antibodies to VZV. The patient was then diagnosed with primary varicella. We share this case to raise awareness of VZV and coexistence of PLEVA, which can lead to a better understanding in the pathogenesis of PLEVA.

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Multifocal Angiomatosis With “Hyaline” Thrombosis: The Presentation of Undiagnosed Waldenstrom's Macroglobulinemia

Hugh Stoddard, MD, Jonhan Ho, MD, and Elizabeth Chao, MD

Department of Dermatology, University of Pittsburgh Medical Center, Pittsburgh, PA.

Both coagulative disorders and hematologic malignancies have been reported, in rare instances, to be associated with the development of angiomatosis containing numerous “hyaline” thrombi. We present a case of previously undiagnosed Waldenstrom's macroglobulinemia that presented with multiple bilateral lower extremity pruritic papules. The papules gradually evolved into multifocal sharply demarcated necrotic ulcerations with violaceous borders and central eschar. Histologically the lesions appeared to be hemangiomas or angiomatosis with distinctive “hyaline” thrombi. The thrombi stained for IgM and Kappa. Immunofixation revealed a monoclonal IgM Kappa which was also positive in the patient's cryoglobulin screen. Taken in isolation these lesions could easily be misdiagnosed as a thrombosed hemangioma. Multifocal angiomatosis has many potential causes, but as other authors have reported, hematologic malignancy should be considered when the “hyaline” thrombi suggestive of cryoglobulinemia are also present.

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Eccrine Gland Induction in Dermatofibroma: A Case Report

Matthew Strausburg, MD, Austin R. Green, BS, and Simon Warren, MBBS

Division of Dermatopathology, Department of Pathology, Indiana University School of Medicine, Indianapolis, IN.

While a variety of reactive epidermal changes have been described overlying dermatofibromas, eccrine gland hyperplasia has not previously been reported in the literature. In this case, we present a 52 year old female with an erythematous papule located on the right leg. A punch biopsy revealed a dermal proliferation of bland spindled to histiocytoid appearing cells with collagen trapping at the periphery consistent with a diagnosis of dermatofibroma. In addition there was notable basaloid epidermal induction overlying the dermal proliferation as well as banal appearing eccrine gland hyperplasia intimately associated within the spindle cell proliferation. A diagnosis of dermatofibroma with eccrine gland induction was rendered. Folliculosebaceous differentiation and epidermal hyperplasia overlying a dermatofibroma are well described phenomena in the literature, however, to our knowledge, eccrine gland induction as not previously been reported. We present this case to identify another benign variant of induction that can occur within dermatofibroma.

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Trichoadenoma on the Forearm: A Case Report of an Uncommon Entity in an Unique Location

Matthew Strausburg, MD,* Nico Mousdicas, MBCHB,† and Terrence M. Katona, DO†

*Division of Dermatopatholoy, Department of Pathology, Indiana University School of Medicine, Indianapolis, IN; and †Roudebush Veterans Affairs Medical Center, Indianapolis, IN.

Trichoadenoma is a rare benign follicular tumor which is typically found on the face. We present a case of an 88 year-old man who presented with a 1 × 1 cm papule on the forearm which clinically resembled a neurofibroma. On histology, sections demonstrated a well-defined dermal proliferation of epithelial islands with epidermoid keratinization similar in appearance to the infundibulum of the hair follicle set in a fibrotic stroma. The differential diagnosis includes nevus comedonicus, desmoplastic trichoepithelioma, and microcystic adnexal carcinoma. A diagnosis of trichoadenoma was rendered based on the benign appearance, epidermoid keratinization, and well circumscribed nature of the tumor. To our knowledge, trichoadenoma has never been reported on the forearm. These tumors are most commonly found on the face, and rare reports have shown lesions on the buttock, thigh, and back. The purpose of this report is to demonstrate a trichoadenoma on the forearm, a previously unreported location for this rare follicular tumor.

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Erythema Elevatum Diutinum Presenting as Plantar Nodules

Leah A. Swanson, MD, David J. DiCaudo, MD, and Steven A. Nelson, MD

Mayo Clinic Arizona, Scottsdale, AZ.

Erythema elevatum diutinum (EED) is a rare, chronic dermatosis that manifests as red-brown or violaceous plaques or nodules involving the extensor surfaces of extremities often overlying joints. We present an unusual case of EED localized only to the plantar feet. A 64-year-old woman presented with a three-year history of tender, enlarging lesions on the soles of the feet. Podiatry and orthopedic surgery were unable to determine diagnosis and considered plantar fibromatosis. Examination of the feet revealed scattered skin-colored, firm 1 cm nodules. Histopathology showed ovoid nodular collections of fibroblasts associated with clefted, sclerotic collagen bundles in the dermis. Leukocytoclastic debris and neutrophils were scattered throughout the fibrotic nodules consistent with diagnosis of EED. Laboratory studies did not reveal infection, autoimmune disorder, or hematologic malignancy. Treatment with dapsone is anticipated. Of the fewer than 10 reported cases of palmar/plantar EED, all demonstrated either typical distribution elsewhere on extensor sites or classic appearance with red-brown nodules. In this atypical presentation with skin-colored nodules isolated to the plantar feet, histopathology was essential to diagnosis, avoiding unnecessary procedures and establishing optimal management.

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Cutaneous B-Lymphoblastic Lymphoma in a Child With Acute Myeloid Leukemia: Identical Chromosomal Translocations Suggestive of Translineage Differentiation

Timothy Tan,* Joan Guitart,† Katrin Leuer,* Lawrence Jennings,* Nobuko Hijiya,‡ and Shunyou Gong*

Departments of *Pathology, †Dermatology, and ‡Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL.

The patient was a 2-year-old female presenting with a scalp mass. She had a history of t(9; 11) (p22; q23), KMT2A (MLL) rearrangement positive, acute myeloid leukemia (AML) originally diagnosed at 8 months of age. At that time, she underwent chemotherapy and achieved complete remission. Histopathologically, the scalp mass revealed a dense dermal infiltrate of medium-sized atypical cells positive for CD19, CD79a, weakly positive for CD20, and negative for CD10, kappa, lambda, MPO, and lysozyme, consistent with B-lymphoblastic lymphoma (B-LBL). Interestingly, she also had concurrently relapsed AML in bone marrow. Genetic studies of the scalp mass and bone marrow both revealed KMT2A (MLL) rearrangement, with a molecularly confirmed MLL-AF9 gene fusion also found in B-LBL, consistent with the genetic abnormality noted 18 months prior at initial diagnosis of AML. To our best knowledge, this case represents the first report of translineage differentiation from AML to B-LBL, and further highlights the importance of comprehensive diagnostic work-up for leukemia cutis/cutaneous lymphoma patients.

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Clinical-Pathological Correlation in a Case of Idiopathic Eruptive Macular Pigmentation (IEMP)

Mehrnoosh Tashakori, MD, PhD, and Adrian H Ormsby, MD

Department of Pathology and Laboratory Medicine, Henry Ford Health System, Detroit, MI.

Idiopathic Eruptive Macular Pigmentation (IEMP) is a rare condition characterized by asymptomatic macular pigmentation. We present a case report of an 8-year-old white girl presenting with diffuse brown non-scaly macules on neck, chest, back, arms and legs with no other symptoms. The onset was abrupt and no suspicious contact with similar rash is stated. Patient has history of asthma; however, she had no recent dermal inflammatory incident. Family history is negative. With clinical suspicion of Lichen Planus (LP), a 4-mm punch biopsy of skin lesion was performed. The histopathological examination revealed increased superficial dermal melanophages with pigment incontinence with no epidermal changes and no increased mast cell count, consistent with IEMP. No definite features of LP, LP variant or LP Pigmentosus were identified. Since IEMP is a self-limiting disease, she received no treatment; however, parents were advised to follow up in case of the eruption of new lesions. After one year of follow up, the pigments has decreased marginally; which is consistent with natural course of IEMP.

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Primary Cutaneous Acral CD8+ T-Cell Lymphoma

Leonardo A. Tjahjono, BS,*,† Mark D. P. Davis, MD,† Thomas E. Witzig, MD,† and Nneka I. Comfere, MD†

*Mayo Clinic School of Medicine, Rochester, MN; and †Mayo Clinic, Rochester, MN.

Winner of Best Poster.

The recently published 2016 revision of the WHO classification of lymphoid neoplasms includes primary cutaneous acral CD8-positive T-cell lymphoma (PCATCL) as a provisional entity. This is a rare indolent lymphoma characterized by papules or nodules on the ear and a dermal infiltrate of CD8-positive T-lymphocytes with cytotoxic marker expression. A retrospective review of a single institutional experience with PCATCL identified three patients (mean age 54; range 49–62) with papules or nodules on the ear. Lesional biopsies demonstrated a dense diffuse dermal infiltrate of atypical lymphocytes with a Grenz zone in two cases and focal epidermotropism in one case. The atypical lymphocytes were predominantly CD3 and CD8 positive with expression of cytotoxic marker TIA1. Staging evaluation failed to reveal systemic disease. Two patients underwent local excision and the third received local radiation therapy all with complete response and no disease recurrence at last follow up 3 months (range 2–5 months). Our cases add to the existing limited literature on the clinical and histopathological features of PCATCL.

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Scleroderma-Like Skin Changes Induced by Checkpoint Inhibitor Therapy

B. Joel Tjarks, Jonathan S. Bleeker, Amy M. Kerkvliet, and Ali D. Jassim

University of South Dakota, Vermillion, SD.

Checkpoint inhibitors have emerged as beneficial therapies in many different types of malignancy. The most common toxicities of checkpoint inhibitors are immune related adverse events (irAEs). As clinical experience with these agents increases, more irAEs have been described. We report a case of scleroderma-like skin changes induced by checkpoint inhibitor therapy. A 61-year-old man was treated with nivolumab for oligometastatic renal cell carcinoma. He initially tolerated the therapy well, but after 16 treatments he began experiencing skin thickening and edema of the abdominal wall which progressed down the trunk and legs. A punch biopsy revealed epidermal attenuation overlying thickened dermal collagen with entrapment and displacement of the eccrine coils with loss of periadnexal adipose tissue. Focally increased plasma cells were present near the junction of the dermis and subcutaneous adipose tissue. Loss of CD34 staining was seen throughout the dermis. These findings were consistent with a diagnosis of scleroderma. After discontinuation of nivolumab and initiation of steroid therapy, the patient's symptomatology significantly improved. This case represents one of the first reports of scleroderma-like changes induced by a checkpoint inhibitor.

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Chronic Granulomatous Disease

Siavash Toosi, John G. Music, Spencer A. Bezalel, and Alina G. Bridges

Division of Dermatopathology, Department of Dermatology, Mayo Clinic, Rochester, MN.

A 21-year-old man presented with a five year history of painful and crusted non-healing skin ulcers involving the trunk, extremities and face. He has been treated with multiple courses of antibiotics. Peripheral blood smear showed morphologically normal leukocytes. A complete systemic workup was negative for infectious and autoimmune conditions. Biopsy from a thigh lesion showed impetiginized serum crust with clusters of gram positive cocci, suppurative dermal inflammation and pigmented macrophages. Multiple cytochemical stains were negative for fungal microorganisms while bacterial cultures revealed Staphylococcus aureus. Neutrophil function test demonstrated decrease in the dihydrorhodamine-positive cells and fluorescence intensity after stimulation with phorbol-myristate-acetate and N-formyl-methionyl-leucyl-phenylalanine. These findings are consistent with the clinical and histopathological presentation of neutrophilic abscesses that can occur in chronic granulomatous disease. Chronic granulomatous disease is caused by mutations in genes that encode the subunits of the NADPH oxidase system involved in organism killing. Here, we highlight the importance of considering primary immunodeficiencies in the differential diagnosis of patients presenting with chronic skin ulcers and a low threshold to biopsy lesions to exclude life-threatening infections.

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Role of the Dermatopathologst in Diagnosis of Neuodegerative Diseases

Siavash Toosi,* Eoin P. Flanagan,† Brian A. Crum,† Joseph E. Parisi,‡ and Alina G. Bridges*

Departments of *Dermatology, †Neurology, and ‡Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.

We report two siblings, a 62-year-old woman and a 64-year-old man, who presented with slowly progressive encephalopathy and neuropathy. Brain MRI showed restricted diffusion at the gray/white matter interface, suggesting a neurodegenerative disease. A brain biopsy from one of the patients showed non-specific findings. A punch biopsy from normal appearing skin of the leg showed intra-nuclear eosinophilic inclusions in eccrine glands, adipocytes and fibroblasts, measuring 1.5-3 µ. The inclusions were immunoreactive with anti-p62 and anti-ubiquitin antibodies. Electron microscopy of the skin demonstrated spherical intranuclear filamentous inclusions. These histologic findings support a diagnosis of neuronal intranuclear inclusion disease (NIID). NIID is a rare neurodegenerative disease. Due to heterogenous nature of the disease, antemortem diagnosis is difficult. We discuss the role of the dermatopathologist in helping with the diagnosis of this challenging disease even in the absence of specific findings on brain biopsy. Also, skin biopsy may be a safe and easy tool to examine familial cases as the genes known to cause NIID have not been identified.

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Explosive Generalized Polymorphous Eruption as a Manifestation of Angioimmunoblastic T Cell Lymphoma (AITCL)

E. E. Gaster, MD, S. Toosi, MD, and A. G. Bridges, MD

Department of Dermatology, Mayo Clinic, Rochester, MN.

AITCL is a rare type of peripheral T cell lymphoma. Most patients present with lymphadenopathy. Skin findings are seen in 50% of patients, occurring at disease onset or late in the disease course. A generalized exanthematous eruption is the most common manifestation, which may be mistaken for a viral exanthem or drug eruption. Our patient had a 4-year history of refractory AITCL with no previous skin involvement. He suddenly developed a polymorphous generalized eruption after initiation of a new chemotherapy regimen. He developed macular erythema coalescing into patches on his bilateral dorsal arms and papulonodules involving face, trunk, and lower extremities. Skin biopsy demonstrated dense angiocentric infiltrate with scattered large pleomorphic lymphocytes. The atypical lymphoid cells were positive for markers of follicular T-helper cells, including CD279 and CXCL13, and gene rearrangement studies showed a clonal T-cell population, confirming a diagnosis of cutaneous AITCL. This unusual clinical presentation highlights the importance of performing skin biopsy to detect disease recurrence or progression in patients with prior history of AITCL.

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Educational Gaps in Molecular Diagnostics, Genomics, and Personalized Medicine in Dermatopathology Fellowship Training

Kristin Torre, BS,* Kristen Russomanno, MD,* Tammie Ferringer, MD,† Dirk Elston, MD,‡ and Michael Murphy, MD*

*UConn Department of Dermatology, Farmington, CT; †Geisinger Medical Laboratories, Danville, PA; and ‡Department of Dermatology, Medical University of South Carolina, Charleston, SC.

Purpose: To evaluate molecular education in dermatopathology fellowship training.

Methods: A 20-question online survey was emailed to all (n = 53) ACGME-accredited US dermatopathology training programs.

Results: Thirty-one of 53 program directors responded. Molecular training is undertaken in 74% of responding fellowships, with levels of instruction varying among dermatology- and pathology-based programs. Almost half (48%) of responding program directors believe fellows are not currently receiving adequate molecular education; although, the majority (97%) expect to incorporate additional instruction in the next 2–5 years. Factors influencing the incorporation of relevant education include perceived clinical utility and ACGME requirements. Potential benefits include increased medical knowledge, improved patient care, and promotion of effective communication with other healthcare professionals. A majority (68%) of responding program directors believe that molecular education should be a requirement in fellowship training.

Conclusions: Discussion among those who oversee fellow education is necessary to best integrate and evaluate teaching of molecular dermatopathology.

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Pediatric Granuloma Annulare With Hypertrichosis: An Atypical Presentation of a Common Dermatosis

Brandon Umphress, MD,* Lacey Kruse, MD,† and Pedram Yazdan, MD‡

*Department of Pathology, Northwestern Feinberg School of Medicine, Chicago, IL; †Department of Dermatology, Ann & Robert H. Lurie Children's Hospital, Chicago, IL; and ‡Department of Dermatology, Northwestern Feinberg School of Medicine, Chicago, IL.

Granuloma annulare (GA) is a granulomatous dermatosis that is a common entity observed in the pediatric population. However, its association and presentation with isolated hypertrichosis has never been documented. We present a case of a 15-year-old male who presented with GA associated with hypertrichosis on the left anterior shin. Full skin examination revealed multiple erythematous-to-violaceous annular plaques on the legs with central clearing and overlying hypertrichosis. Histopathology demonstrated a granulomatous dermatitis surrounding degenerated collagen with central mucin deposition. Upon diagnosis, the patient was treated with topical mometasone twice daily with significant improvement of the plaques and a mild decrease of hypertrichosis at three-month follow-up. To the best of our knowledge, this is the first reported case of pediatric GA associated with hypertrichosis. Recognition of this rare association is important for appropriate diagnosis, management, and patient reassurance.

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Hydroa Vacciniforme-Like Lymphoproliferative Disease: A Case of Delayed Diagnosis

Miranda Uzoma, MD, Richard Jahan-Tigh, MD, Sarah Pinney, MD, and Tony Nguyen, MD

Department of Dermatology, University of Texas, Houston, TX.

Introduction: Hydroa Vacciniforme-Like Lymphoproliferative disease (HVLL) is a rare, EBV-associated disorder with risk of progression to systemic lymphoma. Non-specific histology can make diagnosis difficult. We present a case of HVLL diagnosed after many years of a protracted course and several non-diagnostic biopsies.

Case: A 27-year-old Hispanic male presented with a flaring chronic “bullous eruption” since childhood. Examination revealed numerous bullae on all extremities with necrotic plaques. Prior biopsies revealed either interface dermatitis or superficial and deep lymphohistiocytic inflammation. A new biopsy revealed dense angiocentric and periadnexal CD8+ atypical lymphocytic infiltration. An EBV-encoded RNA in situ hybridization (EBER-ISH) was positive, confirming a diagnosis of HVLL.

Discussion: HVLL is an EBV + cutaneous lymphoproliferative disorder characterized by recurrent papulovesicular eruptions eventuating in necrotic plaques and atrophic scars. Histologically, HVLL demonstrates angiotropism and atypical CD8+ lymphocytic infiltration with EBER-ISH positivity. T-cell receptor gene rearrangement is usually positive. Given its rarity and non-specific histology, risk of delayed diagnosis is high.

Conclusions: Prompt recognition of HVLL is imperative given the risk of progression to systemic lymphoma.

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Cutaneous Syncytial Myoepithelioma: A Nondescript Skin Tumor With Serious Diagnostic Pitfalls

Cameron Wales, MD,* Scott Diamond, MD,* and Brian Hinds, MD†

Departments of *Pathology, and †Dermatology, UC San Diego Health, San Diego, CA.

Background: Cutaneous Syncytial Myoepithelioma (CSM) is a rare tumor with a nondescript clinical presentation.

Case Report: 36-year-old man presented with a tender, 3-mm firm pink papule on the left bicep. Histopathologic examination revealed the top of an intradermal proliferation of spindled, epithelioid, and focally plasmacytoid cells. Partial S100 immunopositivity coupled with EMA and SMA expression was identified, while cytokeratin and p40 were negative.

Discussion: CSM is rare and presents with a broad histologic differential diagnosis. Risk for overdiagnosis looms large with epithelioid sarcoma, epithelioid hemangioendothelioma, and atypical melanocytic proliferations leading the list. Key histomorphologic features include a circumscribed silhouette holding epithelioid, plasmacytoid, and/or spindled cells with ovoid monomorphous nuclei. The immunophenotype is variable with partial S100, SMA, and EMA expression, requiring close cytomorphologic correlation. Cytokeratin/p63/p40 expression may be spurious. EWSR1 rearrangement may be evident on break-apart FISH.

Conclusions: Dermatopathologists should be aware of this peculiar syncytial pattern to avoid misdiagnosis and overtreatment, especially in superficial biopsies of cutaneous myoepithelioma.

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PSA Positivity in Extra-Mammary Paget's Disease

Grant Williams, MD, George Kallingal, MD, and Eric Fillman, MD

San Antonio Military Medical Center, San Antonio, TX.

A 78 year old male with a history of melanoma and prostatectomy for prostate cancer presented with three years of “jock-itch” not improving with topical treatment. Examination showed an erythematous lesion extending from the base of the penis across the left groin crease. PSA at excision was <0.05. Microscopic examination revealed large pale cells with vacuolated cytoplasm singly and in clusters involving the epidermis and dermis. IHC showed the cells as positive for CK7, BerEp-4 (weak), AP15, EMA, CAM 5.2, Mucicarmine (weak) and mCEA and negative for Mart-1, S-100, CK20, TTF-1, p63, alcian-blue, AMACR and cdx-2. This staining profile is consistent with primary extra-mammary Paget's disease (EMPD). Interestingly, PSA was focally positive in solitary cells within the overlying epidermis. The presence of focal PSA positivity in EMPD of the male external genitalia has been reported and is usually patchy and weak, as seen in this case. The IHC staining profile is inconsistent with metastatic prostatic carcinoma. The patient had recurrence of EMPD on his right groin and expired due to treatment effect of metastatic prostate cancer.

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Acrokeratosis Paraneoplastica Presenting in a Chinese Patient With Gastric Adenocarcinoma

Huan Chen,* Dan Xue,† Shite Hu,‡ and Lijun Xue§

*Dermatology Department, Lishui Central Hospital, Lishui, China; †Zhejiang University Second Hospital, Hangzhou, China; ‡Ruian Hospital, Ruian, China; and §Loma Linda University Medical Center.

The object of this study is to present a rare Acrokeratosis paraneoplastica (Bazex's syndrome) in Chinese population. Bazex's syndrome is a very rare paraneoplastic dermatosis characterized by erythematosquamous lesions localized symmetrically at the acral sites. This syndrome is associated mostly with squamous cell carcinoma of the upper aerodigestive tract and metastatic cervical lymphadenopathy. The condition almost exclusively affects Caucasian men older than 40 years. Here we report a case of paraneoplastic acrokeratosis in a Chinese male with gastric adenocarcinoma. A 52-year-old male presented acral hyperkeratosis, and diffuse palmar erythema for four years. When the diagnosis was established, he did not have any symptom of internal malignancy. Four years later, gastroscopy revealed ulcerated lesion of the stomach, and histology showed invasive adenocarcinoma. Surgical tumor removal resulted in significant improvement of skin changes in the first week. To the best of our knowledge, no similar case has been reported previously in Chinese population.

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Epithelioid Angiosarcoma at an Arteriovenous Graft Site in an Immunocompetent Host

Michele L. Zerah, Helena B. Pasieka, and Elizabeth M. Dugan

Department of Dermatology, Medstar Washington Hospital Center/Georgetown University Hospital, Washington, DC.

A 65-year-old African American male presented after seven years of left upper extremity pain and multiple revisions of a former graft site with a non-healing 11.1 cm × 7.5 cm ulceration superior to the left antecubital fossa. The patient tested negative for HIV and had no history of transplants or other malignancies. Examination revealed hemorrhagic punctae, granulation tissue, and rolled, gray borders. Histopathology revealed sheets of large, plump atypical epithelioid cells extending from the deep dermis to the deep soft tissue which demonstrated enlarged nuclei with prominent nucleoli, mitoses and intracytoplasmic microluminae. Poorly formed dissecting vascular spaced were lined by papillomatous, frond-like infoldings. CD-31 antibodies were strongly positive while CD-34 and AE1/AE3 showed focal positivity consistent with an epithelioid angiosarcoma. Antibodies to S-100, Melan-A, CK-7, CK20, HHV-8 and CEA were negative. Of the two-dozen reported cases, only three patients were immunocompetent, and only one other case was at the site of an implanted graft. The majority of reported cases of fistula or graft-associated angiosarcomas have been epithelioid type and the average survival has been reported as 8.8 months. Possible etiologies include upregulation of endothelin-1 in hemodialysis patients and chronic cell proliferation secondary to an implanted foreign body reaction.

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