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Posters Presented at the 22nd Joint Meeting of the International Society of Dermatopathology, February 27–28, 2019, Hilton Crystal City at Washington Reagan National Airport, Arlington, Virginia, USA

The American Journal of Dermatopathology: October 2019 - Volume 41 - Issue 10 - p e116-e130
doi: 10.1097/DAD.0000000000001429
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Diffuse Large B-Cell Lymphoma Arising From Subcutaneous Marginal Zone B-Cell Lymphoma

James Abbott, MD, Caroline Laggis, MD, Ahmad Halwani, MD, Rodney Miles, MD, PhD, and David Wada, MD

University of Utah, Salt Lake City, UT.

Case: A 77-year-old male was diagnosed with marginal zone lymphoma (MZL) that presented as subcutaneous nodules on the back and thigh, with tumor cells situated primarily in the subcutaneous fat. There was partial spontaneous clinical regression of some lesions, but 2 years later, a nodule on the left arm rapidly grew and was biopsied. This 10-cm tumor showed diffuse large B-cell lymphoma (DLBCL). A PCR-based B-cell clonality assay performed on DNA isolated from formalin fixed paraffin embedded tissue from the MZL and DLBCL amplified identical clonal IgH rearrangements, proving clonal identity. The clinical, histologic, and molecular basis of transformation in cutaneous B-cell lymphoma is poorly understood, but this patient’s MZL had preferential involvement of the adipose tissue, an uncommon finding. Herein, we describe an exceptional case of transformation of an indolent subcutaneous MZL to an aggressive DLBCL.

An Interesting Case of Necrobiotic Granulomatous Tattoo Reaction

Prajesh Adhikari, MD*, Ivy Norris, MD†, Laura McGevna, MD†, and Deborah Cook, MD*

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

A 42-year-old man with a 10 pack-year smoking history and a remote history of iritis presented to dermatology clinic for a reaction to tattoos on his back and right ring finger for the previous 5 years. The tattoo sites felt more raised and noticeably itchy. He had other tattoos that did not experience the same reaction. He noted a recent 30-pound weight loss and dyspnea on exertion. Physical exam revealed raised granulomatous papules in linear arrangement with faint surrounding erythema on his back and papulonodules arranged linearly with overlying scale on his right ring finger in association with tattoos. He also had palpable subcutaneous nodules on his central chest and right axilla. Differential diagnosis included granulomatous tattoo reaction and tattoo sarcoidosis. Punch biopsy was performed and contained necrobiotic and sarcoidal granulomatous inflammation associated with exogenous pigment deposition. Further workup revealed cervical and hilar lymphadenopathy consistent with sarcoidosis. The finding of necrobiosis in the setting of a tattoo has rarely been described.

A Rare Vegetative Presentation of IgA Pemphigus

Maria D. Avila*, Christine S. Ahn*, Omar P. Sangüeza*, and Lindsay C. Strowd†

Departments of *Pathology and †Dermatology, Wake Forest School of Medicine, Winston-Salem, NC.

IgA pemphigus is a rare pemphigus subtype with variable clinical, histopathologic, and direct immunofluorescence (DIF) features. We present a case with histopathologic features typical of intraepidermal neutrophilic IgA pemphigus and clinical features of both IgA pemphigus and pemphigus vegetans. A 16 year-old boy with May Thurner Syndrome presented with a 4-month history of pruritic bullae on bilateral lower extremities. On physical examination, there were tense bullae in an annular configuration with a central crust and vesiculopustules at the periphery. Histologically, intraepidermal collections of neutrophils were seen. DIF demonstrated strong IgA and weak C3 intercellular deposition, and granular IgG along the basement membrane. Despite initiating methotrexate, the lesions evolved into hypertrophic, verrucous plaques resembling pemphigus vegetans. Additional biopsy demonstrated intraepidermal neutrophils without significant acantholysis. The clinicopathologic and immunofluorescence findings were most consistent with an uncommon presentation of IgA pemphigus, intraepidermal neutrophilic (IEN) type. IgA pemphigus is a rare entity that can demonstrate variable findings. This is the first reported case of IgA pemphigus with overlapping features of pemphigus vegetans. Establishing the diagnosis is important as therapy differs from other pemphigus variants.

Focal Dermal Melanocytosis Harboring NTRK2 Mutation Presenting as Cutis Verticis Gyrata

V. Alegría-Landa, L. Prieto-Torres, L. Núñez-Hipólito, and L. Requena

Department of Dermatology, Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain.

Dermal melanocytoses are peculiar melanocytic lesions characterized by a bluish discoloration of the skin being the entities named depending of the involved body areas. This group of lesions are classically considered as variations on the theme of blue nevus, apparently linked by common initiating mutations involving GNAC and GNA11 genes. On the other hand, cutis verticis gyrata is not an entity itself but a descriptive term that refers to the presence of folds and furrows resembling the convolutions of the cerebral cortex. We present a 41-year-old woman with a lesion in the parieto-occipital region that had been present at least since childhood. Physical examination showed an intensely bluish well-circumscribed lesion of 10 × 7 cm with a striking cerebriform aspect. Histopathologic study showed heavily pigmented elongated dendritic melanocytes scattered throughout the dermis among undisturbed collagen fibers and without accompanying melanophages. By directed massive sequencing of the mutational state of 161 genes, NTRK2 c.1010C>G p. was found. The exceedingly rare occurrence of a focal dermal melanocytosis harboring a mutation in a gene whose fusions have been implicated in primary and metastatic melanoma, that presented as a CVG are discussed. The relationship between dermal melanocytoses, blue nevus and congenital melanocytic nevus is reviewed and a practical classification for CVG is proposed.

Methimazole Induced Cutaneous Leukocytoclastic Vasculitis (LCV) in Anca Negative Patient

Mohamed Alhamar, MD and Adrian Ormsby, MD

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

A 64 y.o. Caucasian female with past medical history of hypertension, diabetes, asthma, and Graves’ disease with progressive dyspnea secondary to exudative large pleural effusion with a differential diagnosis of neoplastic, collagen vascular or drug induced lung disease. The patient was admitted with uncontrolled hypertension and Graves’ disease and started on metoprolol, lisinopril and methimazole. One week later she developed small red macules on her forearms, hands, and ankles (Figures 1 and 2). ANA was positive but ANCA was negative. Left forearm punch biopsy showed prominent superficial perivascular neutrophilic leukocytoclasia and purpura with abundant eosinophils (Figures 3 and 4) and accompanying positive DIF findings (IgG & C3: 3+ interrupted granular staining in superficial dermal vessel walls. IgM, IgA & Fibrinogen: negative) favoring a drug associated ANCA-negative LCV. The macular rash improved after discontinuing methimazole. In conclusion, the association between DIF positive LCV and Methimazole with a negative ANCA is rare and should be considered in the clinical differential of drug induced palpable purpura indicating skin biopsy and DIF confirmation.

Strangulated and Necrotic Acrochordon: A Cause of Widespread Skin Necrosis

Albert Alhatem, MD, Sara Behbahani, MS, Marcus L. Elias, BS, Shreya Patel, BS, Radhika Shah, PharmD, Jose Espinal-Mariotte, MD, and William C. Lambert, MD, PhD

Rutgers New Jersey Medical School, Newark, NJ.

A 61-year-old African American male presented with 70% body skin necrosis. On his left upper back was a dark brown polypoid lesion measuring 0.9 × 0.6 × 0.3 cm. The lesion was excised and sent for histopathological evaluation. Microscopic examination revealed an acrochordon, with a papillary dermis composed of loose collagen fibers and dilated capillaries and lymphatic vessels, strangulated and necrotic. Twelve hours later, the patient improved clinically and 2 days later was discharged home. Follow-up visits showed complete recovery of the widespread necrosis. Acrochordon is a common benign neoplasm that occurs in middle-aged and elderly subjects found mainly in the intertriginous skin. The etiology is unclear, but there is an association with diabetes mellitus (DM), obesity, friction, acromegaly, colonic polyps, and human papilloma virus (HPV). The main feature is fibroblast proliferation and epidermal hyperplasia. We present a rare case of widespread skin necrosis, which healed completely after removing a strangulated and necrotic acrochordon.

An Isolated Case of Sebaceous Carcinoma: Muir-Torre Syndrome?

Sara Behbahani, MS,* Marcus L. Elias, BS,* Steven Skula, MBBS,* Archana Babu, MS,* Albert Alhatem, MD,† Qing Wang, MD, PhD,* and William C. Lambert, MD, PhD*

*Rutgers New Jersey Medical School, Newark, NJ.

A 65-year-old African American male with no known pertinent past medical or family history presented to the clinic with a solitary 2.8 cm × 1 cm × 1 cm mass on his occipital scalp. An excision was taken. The lesion was composed of proliferating, mature sebaceous glandular structures in some areas and other areas structures that were consistent with sebaceous ducts. Some areas showed well-differentiated cells with no atypia but other areas showed relatively undifferentiated cells typical of sebaceous carcinoma. Because of the size of the tumor and appearance of some atypical cells, the lesion was diagnosed as sebaceous carcinoma. Sebaceous carcinoma may occur in isolation in 2 important clinical settings: (1) nevus sebaceous (Jadassohn) (2) as part of the Muir-Torre syndrome, a subtype of Lynch Syndrome. Direct treatment for this consists of wide local excision and follow-up colonoscopy to rule out colon cancer, which occurs in increased frequency in Muir-Torre syndrome. Given the patient’s age and no history of a prior colonoscopy, the patient was referred to a gastroenterologist for colonoscopy. Results showed colonic polyps confirming our suspicion of Muir-Torre syndrome.

Mycosis Fungoides With Granuloma Annulare-Like Features: Case Report and Review of Literature

Shaymaa Al-Loh Ashi, MD,* Yan Xiang, MD, MBA,* and Carrie Ann Cusack, MD†

*Drexel University, Pathology Department, Philadelphia, PA; and †Dermatology Associates of South Jersey, Mount Laurel, NJ.

Objective: Mycosis fungoides is a great mimicker with reports documenting MF with clinical and histologic features of benign dermatoses. MF mimicking granuloma annulare is an unusual histologic variant. Only some of the reported cases have demonstrated classical epidermal changes of MF.

Methods: Seventy-one year-old male patient presented with pruritic erythematous scaly patches and plaques on the trunk and extremities for 2 years. The eruption was diagnosed and treated as psoriasis with topical and systemic therapy, with variable responses.

Results: Biopsy revealed atypical epidermotropic lymphocytes and Pautrier’s microabscesses. The dermis showed lymphohistiocytic infiltrate, with palisading atypical lymphocytes and wiry collagen. The atypical lymphocytes are positive for CD3 and CD4. T-cell receptor gamma gene rearrangement study performed on peripheral blood revealed a monoclonal spike. PET/CT scan did not reveal any evidence of metastasis.

Conclusions: Rare cases of MF with GA-like features were reported in the literature so far. High index of suspicion of atypical dermal lymphohistiocytic infiltrates allow for a correct diagnosis.

Syringocystadenocarcinoma Papilliferum Presenting as a Spindle Cell Lesion

Michael G. Astudillo, MD, Rosalynn M. Nazarian, MD, Ellen K. Roh, MD, and Ruth K. Foreman, MD, PhD

Massachusetts General Hospital, Boston, MA.

Syringocystadenocarcinoma papilliferum (SCACP) is a rare entity. We report a case of SCACP in a 71-year-old man who presented with a rapidly enlarging nodule on the occipital scalp that had been present since birth and was draining clear fluid. The patient had no pertinent past medical history. A shave biopsy demonstrated a carcinoma composed of infiltrative spindled cells with apparent lumen formation and atypical mitotic figures. An associated syringocystadenoma papilliferum was present. The tumor was excised and histological examination of the resection specimen revealed additional tumor morphologies, including squamoid and glandular foci, and areas resembling lymphoepithelioma-like carcinoma. In addition to the associated syringocystadenoma papilliferum, there were areas suggestive of a background nevus sebaceus. Overall, the histological features, proximity to a syringocystadenoma papilliferum, and positive immunohistochemical staining for cytokeratins supported the diagnosis of SCACP. This case highlights SCACP with unusual tumor histomorphology composed predominantly of spindled cells with apparent lumen formation which posed a diagnostic challenge on the initial shave biopsy.

Massive Squamous Cell Carcinoma Arising From Chronic Gluteal Hidradenitis Suppurativa

Catherine Baker,* Anh Pham,† Shaun Cooper,* Molly Cowdrey,‡ Dorothea Barton,*,† Jonathan Glass,*,† M. Shane Chapman,*,† and Joi B. Carter*,†

*Dartmouth Geisel School of Medicine, Hanover, NH; †Section of Dermatology, Dartmouth-Hitchcock Medical Center, Lebanon, NH; and ‡Lahey Hospital & Medical Center, Burlington, MA.

A 59-year-old man with chronic hidradenitis suppurativa (HS) presented to dermatology with multiple rapidly enlarging, painful, ulcerated nodules and tumors on his buttocks, 2–7 cm in diameter. The patient had longstanding perineal and gluteal HS that had responded minimally to antibiotics, prednisone, and TNF-inhibitors. Biopsy of the tumors revealed dermal nests of pleomorphic squamous cells consistent with moderately differentiated squamous cell carcinoma (SCC). Computed tomography scan revealed inguinal node metastases. Treatment with acitretin and chemotherapy was attempted but repeatedly delayed due to wound infections. Palliative radiation was initiated, but the SCC continued to transform. Two months after presentation, the tumors had coalesced into several giant (>20 cm) fungating ulcerative masses that disfigured the entire buttocks and lower back. The patient transitioned to hospice and died shortly thereafter. This case exemplifies the importance of closely monitoring men with severe gluteal HS, with a low threshold to biopsy lesions unresponsive to immunosuppression.

A Rare Case of Secondary Syphilis With Associated Granulomatous Inflammation

Latrice Hogue,* Suwash Baral,† Christine S. Ahn,† Zeynep Akkurt,* and Omar P. Sangüeza*,†

Departments of *Dermatology and †Pathology, Wake Forest School of Medicine, Winston-Salem, NC.

Secondary syphilis is considered a great imitator and can have a wide range of clinicopathologic presentations. We describe a case of secondary syphilis presenting as a non-specific rash with atypical histologic features. A 52-year-old man with a history of HIV presented with a 1-week history of erythematous rashes on his trunk and arms, sparing the palms, soles and oral mucosa. He was otherwise afebrile and asymptomatic. Histopathologic examination of the skin revealed superficial and deep perivascular granulomatous inflammation and epithelioid granulomas mixed with lymphocytes and plasma cells. Stains with PAS, GMS, and AFB were negative, and treponemal stains demonstrated spirochetes throughout the dermis. Serum treponemal tests were confirmatory. The patient was successfully treated with one dose of penicillin G benzathine. In rare cases, secondary syphilis can demonstrate granulomatous inflammation mimicking other granulomatous diseases and infectious processes. Syphilis should remain within the differential for clinicians and pathologists alike and confirmatory tests should be performed to prevent missing the diagnosis of a treatable disease.

Primary Cutaneous Cryptococcosis in an Elderly Pigeon Breeder

Meghan Beatson, BS,* Michael Harwood, MD,† Vail Reese, MD,‡ and Leslie Robinson-Bostom, MD*

*Department of Dermatology, Alpert Medical School of Brown University, Providence, RI; †Department of Dermatology, Yale New Haven Hospital, New Haven, CT; and ‡Union Square Dermatology, San Francisco, CA.

An otherwise healthy 80-year-old male pigeon breeder presented with a 3 to 4-week history of ulcerated nodules and plaques on the left side of his face and right ear, which began as pruritic papules that progressively ulcerated and developed a yellow crusted exudate. Physical exam revealed 2 well-demarcated crusted plaques on his left cheek, measuring 2.4 × 2.1 cm and 2.6 × 2.8 cm. The patient’s right ear showed an ill-defined, ulcerated plaque with yellow crust extending into the external auditory canal. Punch biopsy of the superior facial lesion and ear lesion demonstrated granulomas with surrounding mixed inflammation. Spores with a thick clear capsule were seen on H&E stain. PAS and GMS stains demonstrated narrow budding yeast forms within giant cells and histiocytes. Culture of the cheek and ear demonstrated Cryptococcus neoformans. Work up for disseminated cryptococcosis was negative. The patient was diagnosed with primary cutaneous cryptococcosis, and started on Fluoconazole 200 mg qd. After 2 months of therapy, the lesions completely resolved.

Cutaneous Syncytial Myoepithelioma

Robert Bednarek, MD and Wells Chandler, MD

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

Background: Cutaneous syncytial myoepithelioma (CSM) is a rare histologic subtype of myoepithelial neoplasm that is clinically benign.

Case Description: A 47-year-old female presented with a 1-month history of an enlarging 1.5 cm soft, pink, exophytic nodule above the right elbow. Histopathologic evaluation revealed a well-circumscribed nodule of spindle cells, epithelioid cells, and adipocytes embedded in a fibromyxoid stroma. Positive immunohistochemical stains included S100, S100a6, EMA, and SMA, while cytokeratin AE1/AE3, P63, HMB-45, and Sox-10 were negative.

Discussion: CSM is a rare myoepithelial neoplasm typically manifesting as a cutaneous nodule with male predominance and predilection for the extremities. The angulated sheets of syncytial myoepithelial cells characteristic of this tumor mimic invasive carcinoma at low microscopic magnification. However, CSM is regarded as a benign entity and rarely recurs. On histopathology, spindled or epithelioid cells with palely eosinophilic syncytial cytoplasm grow in sheets within the dermis. CSM is positive for S100 and EMA, and in contrast to most myoepithelial neoplasms, is generally negative for cytokeratin staining. EWSR1 gene rearrangement is common and molecular testing may help in confirming the diagnosis. Treated with excision is curative.

Cutaneous EBV Positive Diffuse Large B-Cell Lymphoma: Post-transplant Lymphoproliferative Disorder

Daniel Bergman, MD, David J. DiCaudo, MD, Steven A. Nelson, MD, Aaron Mangold, MD

Mayo Clinic, AZ.

Post-transplant lymphoproliferative disorders (PTLD) are common neoplasms in solid organ transplant recipients. Most are B-cell in origin and EBV positive. PTLD with localized cutaneous presentation, especially diffuse large B-cell lymphoma (DLBCL), is rare. A 71-year-old woman, with donor EBV positive renal transplant, presented with a rapidly growing tender nodule to her left shin. Examination revealed a palpable 2.6 × 4 cm tumor with central ulceration. Histopathology showed sheets of blast-like pleomorphic cells CD20, CD30, and MUM-1 positive, with EBV expression by in situ hybridization. FISH was negative for MYC, BCL-2, and BCL-6. Bone marrow biopsy and PET-CT were unrevealing, except for known cutaneous disease. She was treated with rituximab, clearing her EBV, but required radiation therapy to resolve the lymphoma. She remains disease free 6-months later. PTLD with localized cutaneous EBV-associated DLBCL is rare. Histopathology is paramount for diagnosis, and helps distinguish prognostic variations between subsets of cutaneous T and B-cell PTLDs (4, 5). This case adds to the few reports of PTLD with cutaneous EBV-associated DLBCL, successfully treated with rituximab and radiation therapy.

A Family With Pseudoxanthoma Elasticum (PXE) and a Unique Histopathological Feature

K. Bowerman, D. Sharma, L. Robinson-Bostom, and L. Bercovitch

Department of Dermatology, Warren Alpert Medical School, Brown University, Providence, RI.

A 68-year-old woman presented with thickened, loose skin on her neck, antecubital fossae, and groin, first noticed at age 22. She had known diabetic retinopathy complicated by retinal bleeding. Her sister and son both have lax, doughy axillary skin without retinal findings. Examination showed markedly lax axillary and inguinal skin with yellow papules coalescing into linear plaques. Peripheral pulses were normal. Visual acuity was 20/30 OD, 20/25 OS. There were no angioid streaks, peau d’orange or macular abnormalities. Punch biopsy revealed clumped and curled slightly basophilic calcified elastic tissue embedded in a prominent and distinctively hyalinized collagenous stroma. Verhoeff-van Gieson and von Kossa stains highlighted extensive calcium deposition on this large dermal zone of altered/clumped elastic fibers, consistent with PXE. Histopathologically, PXE presents with clumped elastic fibers in the mid/lower dermis that stain positively for calcium. The hyalinized collagenous stroma in this case is unique and, to our knowledge, has never been described in PXE. The complete absence of angioid streaks suggests a novel phenotype. Genotyping is pending.

Cutaneous Cholesterol Embolization Mimicking Calciphylaxis

Jessika Davis, MD,* Warren Piette, MD, *and Marylee Braniecki, MD†

*Department of Dermatology, Cook County Health & Hospitals, Chicago, IL; and †Department of Pathology, U of Illinois at Chicago, Chicago, IL.

Cutaneous cholesterol embolization (CCE) is caused by a widespread release of cholesterol crystals from an atheromatous plaque that leads to vascular occlusion. It most often occurs following vascular intervention such as surgery or cardiac catheterization. CCE may manifest as livedo reticularis, acral cyanosis, ulcers, nodules or purpura. It most commonly occurs on the distal lower extremities. We share an unusual case of CCE that presented with an atypical skin distribution of retiform necrotic ulcers involving the flank, thigh and hips that mimicked the appearance of calciphylaxis. Patient was a 69-year-old lady with past medical history of hypertension, hyperlipidemia, and chronic kidney disease who was recently hospitalized at an outside hospital for a myocardial infarction for which she underwent cardiac catheterization. She presented to the ER with complaints of painful skin lesions and 4th toe pain, but suddenly developed cardiac symptoms. Her troponin was elevated at 16 and a left heart catheterization was performed showing multiple vessel disease. Skin biopsy from the thigh revealed a deep dermal vessel plugged with cholesterol needles associated with an overlying suppurative necrosis. We share this case as to raise awareness that CCE does not always present in the distal extremities but can occur proximally and can clinically mimic calciphylaxis.

Linear Nodular Plaque of Hypertrophic and Follicular Porokeratosis Occurring on the Panniculus

Ammar Karo,* Mohammad Shokouh-Amiri,* Maria Tsoukas,† Stephanie Wang,† Kurt Ashack,† and Marylee Braniecki*

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

Porokeratosis is a group of distinct cutaneous lesions characterized histologically by the presence of coronoid lamellae. We share this unusual case of porokeratosis with coexistent hypertrophic and follicular variants, presenting as a giant, arcuate hyperkeratotic lesion on the panniculus. Clinically, the lesion presented as giant linear nodular plaque occurring along the apical ridge of the panniculus with keratinous spikes projecting from the skin surface corresponding to the folliculocentric keratosis. This lesion lacks the usual atrophic center which is commonly seen in other variants of porokeratosis. However, histologically, we do see numerous follicular coronoid lamellae within the hypertrophic plaque associated with an underlying band of lymphocytic infiltrates in the papillary dermis. This case highlights the rarity of this cutaneous lesion, its location plus the coexisting variants of porokeratosis. More Importantly this lesion was completely excised since malignant transformation can be associated with porokeratosis.

Extramammary Paget’s Disease Colonizing a Perianal Fibroepithelioma of Pinkus

Jennifer Brooks, MD,* Robert Long, MD,† and Wells M. Chandler, MD*

*Department of Dermatology, Geisinger Medical Center, Danville, PA; and †Department of Dermatology, Evangelical Community Hospital, Lewisburg, PA.

Fibroepithelioma of Pinkus (FEP), a basal cell carcinoma variant, as well as fibroepitheliomatous hyperplasia have been reported in association with Paget’s disease, especially anogenital extramammary Paget’s disease (EMPD). We present a case which highlights this unusual phenomenon. A 64-year-old male presented with a 1-year history of a 5 cm perianal eroded plaque. Biopsy of the plaque revealed an arcade of hyperplastic epidermal rete with a basal palisade and associated fibromucinous stroma, diagnostic of FEP. A population of subtle pleomorphic cells which stained strongly for CDX2 and CK20, moderately positive for villin, weakly positive for SATB2, and negative for CK7 and synaptophysin percolated through the FEP. The immunohistochemistry indicated a colonic immunophenotype of secondary EMPD and evaluation for an underlying colorectal malignancy is underway. The literature has described 17 cases of FEP tumors or fibroepitheliomatous hyperplasia arising in Paget’s disease. A true interrelationship between FEP and extramammary Paget’s disease is favored over a collision phenomenon. Further studies are needed to elucidate the pathogenesis of this finding.

Non-staining Method for the Evaluation of Urate Crystals in Gout

Ijeuru Chikeka, MD and George Niedt, MD

Columbia University Medical Center, New York, NY.

Gout is an inflammatory arthritis caused by hyperuricemia and the deposition of monosodium urate crystals in joints which often leads to debilitating clinical symptoms and functional impairment. It typically occurs in the skin during the chronic tophaceous stages as a nodule on the lower and upper digits and helix. Histologically, when properly fixed in alcohol, gouty tophi appear as deposits of brown, negatively birefringent, needle-shaped crystals. When the diagnosis in not suspected and the specimen is submitted in formalin fixative, the urate crytals are dissolved, leaving behind amorphous, basophilic matrix surrounded by foreign body giant cells, histiocytes, chronic inflammation, and fibrosis. While the histologic appearance of tophi is usually diagnostic, special techniques are sometimes required, particularly when histologic features are less characteristic and crystal deposits are scant. Here we describe a non-staining method which demonstrates urate crystals in formain-fixed, paraffin-embedded tissue and we evaluate its efficacy against standard H&E-stained sections in 10 cases of cutaneous gout. We also review the literature regarding existing adjunctive stains and methods which help to facilitate the evaluation of crystals for definitive diagnosis.

Intravascular Papillary Endothelial Hyperplasia on the Penile Shaft

William Day, BS,* Elizabeth Taylor, DO,† and Nicholas F. Logemann, DO†

*Eastern Virginia Medical School, Norfolk, VA; and †Department of Dermatology, Walter Reed National Military Medical Center, Bethesda, MD.

Intravascular papillary endothelial hyperplasia (IPEH) is a benign vascular proliferation characterized by an unusual pattern of thrombus organization within a vein or within one or more components of a vascular abnormality. Though a non-neoplastic reactive process, IPEH remains an important histopathologic entity due to its resemblance to angiosarcoma and other vascular tumors. Common sites for occurrence include the head and neck, fingers, and trunk with more uncommon sites including oral cavity and other mucosal surfaces. Here, we present the rare presentation of IPEH on the shaft of the penis confirmed via histopathology showing a re-canalizing thrombus with papillary endothelial proliferation, positive CD31/CD34 staining, and negative HHV-8 staining.

Kaposi Sarcoma in Afghanistan: Seven Cases

Richard Dunn, MD,* Jerad Gardner, MD,* Benjamin Stoff, MD,† Omer Malakzai, MD,‡ Ryan Campbell, MD,* and Josette McMichael, MD†

*University of Arkansas for Medical Sciences; †Emory University; and ‡CURE International Hospital of Kabul, Afghanistan.

Kaposi sarcoma (KS) has been well studied, especially in Africa, where both the endemic and HIV-related subtypes have a high incidence. In Afghanistan, however, there is very little data about KS or HIV, and some evidence to suggest the rates are higher that what has been reported. In this case series, we present 7 well-documented KS cases; 6 classic, and 1 HIV-related, collected over a 4-year period via a teledermatopathology collaboration between a teaching institution in Kabul, Emory University, and UAMS. The cases are predominantly men in their 60s, in the tumor stage of KS, presenting on the lower extremities, with variable presentation on the hands, torso, and oral mucosa. This study will add valuable information to the body of knowledge for KS in this region and hopefully increase awareness of the disease, along with improved outcomes.

A Case of Bullous Porokeratosis

E. L. Foster, L. H. Morrison, S. Mengden Koon, and K. P. White

Oregon Health & Science University, Portland, OR.

A 68 year old male with history of jejunal liposarcoma admitted for resection developed a blistering pruritic rash 1 day after surgery. The rash began on the right arm and spread to his legs, abdomen, back and buttocks, sparing his face, hands and feet. On physical exam, the patient was an ill-appearing, elderly male with labored breathing. Skin exam showed many 2–5 mm dark pink to orange papules and vesicles, with few erosions and hemorrhagic crusts. Two 4 mm punch biopsies showed vesiculobullous and mixed dermatitis with coronoid lamellae. Direct immunofluorescence of perilesional skin showed weak granular deposition of IgA, IgM and fibrinogen within the walls of superficial dermal blood vessels, with no granular IgA, no specific deposition of complement, and no linear deposition of C3. A diagnosis of bullous porokeratosis was made. Induction of porokeratosis in association with immunosuppression and infection has been reported only once before. Therefore, no standard treatment exists. We prescribed triamcinolone 0.1% ointment, which eased the patient’s pruritus. Unfortunately, after resolving his septic shock, he had an aspiration event and died after being placed on comfort care.

Langerhans Cell Histiocytosis With Clinicopathologic Features of Hidradenitis Suppurativa

Rony A. François, MD, PhD, Diana S. Braswell, MD, and Kiran Motaparthi, MD

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

Langerhans cell histiocytosis (LCH) is a histioproliferative malignancy which may present with a variety of cutaneous and systemic manifestations. Here we report 2 patients with LCH, with clinical and histopathological features simulating hidradenitis suppurativa (HS). In the first case, a 21-year-old African-American man presented with ulcerated plaques in the axillae with sinus tracts and suppurative discharge. In the second case, a 34-year-old male presented with ulcerated nodules with purulent drainage in the axillae and inguinal folds. In both patients, the clinical morphology and involved anatomic sites led to initial presumptive treatment for HS. However, given the presence of pulmonary disease, histopathologic confirmation was sought. In both patients, there was a dermal infiltrate composed of large cells with eosinophilic cytoplasm and bean-shaped nuclei with admixed scattered lymphocytes, few giant cells and scattered eosinophils. Neoplastic cells were strongly positive for S-100 and CD1a. Additionally, foci reminiscent of ruptured cyst or follicle, along with perifollicular neutrophils and plasma cells, were correlated with clinically-observed sinus tracts. HS-like LCH is typified by ulcers and draining sinuses of axillary and inguinal skin, occurs in dark-skinned patients, and is associated with pulmonary involvement.

TERT Promoter Mutation Analysis in Spitzoid Melanoma

Rony A. François, MD, PhD,* Diana S. Braswell, MD,* Kimberly J. Newsom, PhD,† and Kiran Motaparthi, MD*

*Department of Dermatology, University of Florida College of Medicine; and †Department of Pathology, University of Florida College of Medicine, Gainesville, FL.

Molecular evaluation including fluorescence in situ hybridization (FISH), comparative genomic hybridization (CGH), and next-generation sequencing (NGS) have been increasingly employed to classify Spitz nevi, atypical Spitzoid neoplasms, and Spitzoid melanomas. TERT promoter sequencing is recently described in aiding this distinction. A 46-year-old woman presented with a tender, erythematous 9 mm papule on the flank which quickly enlarged over 4 months. Histopathologic examination demonstrated a symmetric neoplasm, with epidermal hyperplasia and junctional nests composed of large spindle/epithelioid melanocytes surrounded by clefts. Eosinophilic globules were present. The dermal component formed dense nests with focal sheet-like appearance, without evident maturation or single cell dispersion. Typical mitotic activity including a marginal mitosis was observed. Of note, lymphovascular invasion was identified. p16 expression was retained. HMB-45 demonstrated weak expression, without gradient. Ki-67 demonstrated a proliferation index of approximately 5%. In a 116-gene NGS panel, no pathogenic or driver mutations were identified. While TERT promoter mutation analysis appears to be a promising tool for differentiation of Spitz nevus from Spitzoid melanoma, this may not be a wholly sensitive feature, even in morphologically diagnostic cases.

Cutaneous Metastases of Metastatic Neuroendocrine Tumor With Unknown Primary Site

Ryan Gall* and Daniel DiBlasi†

*Uniformed Services University, Bethesda, MD; and †Walter Reed National Military Medical Center, Bethesda, MD.

Neuroendocrine tumors are rare neoplasms that can secrete hormones, neurotransmitters, neuromodulators and neuropeptides. Metastatic disease occurs in about 13% of cases, with cutaneous metastasis occurring in a small minority of these. Clinically, the presentation of cutaneous metastases of neuroendocrine carcinoma is highly variable, but most often presents as subcutaneous nodules. These can be solitary or multiple, painful or asymptomatic, range in size from 2.5 mm to 4 cm, and can have varying overlying skin changes. In this case, we present a 63 year old female patient diagnosed with neuroendocrine cancer with unknown primary, originally presenting with multiple hepatic and pancreatic metastases. The patient later developed a painful subcutaneous nodule of the upper back with no overlying skin changes, for which the patient was referred to dermatology. Punch biopsy results proved consistent with metastatic neuroendocrine tumor. This case of an uncommon malignancy that very rarely metastasizes to the skin illustrates how the dermatologist may assist in assessing disease progression through identification of cutaneous lesions.

Atypical Squamous Proliferations: A Review of Management and Final Diagnosis

Ruby Gibson, BS,*,† Marie Han, MD,‡ Kate Kimes, MD,‡ Heather Layher, DO,‡ and Scott Dalton, MD, PhD†

*University Health Science Center; †San Antonio Military Medical Center; and ‡San Antonio Wilford Hall Ambulatory Surgical Center.

Introduction: Atypical squamous proliferation (ASP) is a descriptive pathologic diagnosis of keratinocyte atypia that currently has minimal recommendations for the best practice for the management. Our objective was to review current common managements and outcomes of ASP.

Methods: We retrospectively reviewed skin lesions reported as ASP between 2004 and 2014 for management and final outcomes.

Results: A total of 771 ASP species were found. The original pathologist favored a malignant process in 36% of the lesions, benign in 28% of lesions, and listed both benign and malignant in 35% of lesions. The most common treatments were excision in 33.6%, rebiopsied in 14.5%, Mohs in 11.8%, liquid nitrogen in 2.7%, 5-Fluorouracil in 1.2. After management, 369 lesions received a second diagnosis, 28% of which were malignant.

Conclusions: In biopsies that are leaning towards an ASP diagnosis, a dermatopathologist should be consulted in order to lean towards a definitive diagnosis to assist the dermatologist with management decisions.

Melanoma of the Buttocks: A Rare Occurrence in a Non-sun Exposed Anatomic Site

Yan Zhou and Alessio Giubellino

University of Minnesota, Minneapolis, MN.

The recent updated edition of the World Health Organization Classification of Skin Tumours (IV edition) emphasizes the importance of sun damage in the onset of distinct melanocytic lesions. Melanomas on non-sun exposed areas show distinct clinicopathological features and mutational profiles. We explored the clinic-pathologic characteristics of malignant melanoma in an anatomic site with no or low sun exposure: the buttocks. We retrieved cases of malignant melanomas in this location occurring in the last fifteen years at our hospital system. Of 22 cases found, 17 were primary malignant melanomas with a prevalence of female (14), spanning an age range from 21 to 71 years old (median 49). The majority of the cases were classified as superficial spreading melanoma (6) or nodular type (5). Of the 17 cases, only 2 had available molecular study results, with one case with no detected mutations, and one case with a BRAF V600E mutation. Four cases were metastasis occurring in the buttocks as consequence of widespread dissemination from other anatomic sites. One case was a borderline lesion.

A Challenging Case of Psammomatous Melanocytic Schwannoma Mistakenly Diagnosed as Metastatic Melanoma

Andrea Boni and Alessio Giubellino

Spectrum Healthcare Partners, South Portland, ME; and University of Minnesota, Minneapolis, MN.

Psammomatous melanocytic schwannoma is a rare melanin-producing tumor of Schwann cells with a histopathologic and immunohistochemical profile largely overlapping with malignant melanoma. While about half of cases present in patients with Carney complex, it can be sporadic and may present in skin, root ganglia or visceral organs. The majority of these lesions are benign, but about 10% can be malignant with associated metastasis. A 32-year-old patient with Carney complex presented with hematochezia and a colonoscopy was performed. A fungating 5 cm mass was located in the left colon and a biopsy was obtained. The lesion was originally reported as metastatic malignant melanoma. A complete resection of the lesion was performed and on further histologic and immunohistochemical analysis of this specimen, the tumor was correctly classified as a psammomatous melanocytic schwannoma in the setting of an underlying Carney complex. Key to the correct diagnosis were the presence of psammoma bodies and low mitotic rate. This case further emphasize the important knowledge of this rare entity by both general pathologists and dermatopathologists.

Mycosis Fungoides, Lymphomatoid Papulosis, or Both?

Jeenal Gordhandas, MD* and Qinghong Yang, MD, PhD*,†

*University of California San Diego, CA; and †VA San Diego Healthcare System, CA.

A 68-year-old male presented with 1-year history of extensive ill-defined erythematous patches and occasional associated small papules on the trunk, arms and legs. On histologic exam, the papular areas show many large markedly pleomorphic atypical T cells that are CD30+ whereas the surrounding patch areas show histologic findings characteristic of early stage mycosis fungoides (MF) with many epidermotropic atypical small-sized T lymphocytes with cerebriform nuclei. PCR-based TCR gene rearrangement studies demonstrate a single peak in both the patch and the papular areas. The clinical, morphological and molecular findings are most consistent with early patch stage mycosis fungoides (MF) co-exists with likely clonally-related lymphomatoid papulosis (LyP), which is very rare with only a few cases been reported in the literature. Further studies of these rare cases may help shed light on the tumorigenesis of MF and LyP.

Recurrent Atypical Intracranial Meningioma Presenting as “Glabellar Cyst”: Report of a Case

Jeenal Gordhandas, MD,* William Nahm,† Walter Nahm, MD,‡ and Brian Hinds, MD*

*UC San Diego, CA; †Pomona College, Claremont, CA; and ‡University Dermatology Group, CA.

Meningiomas are extracerebral intracranial neurocristic tumors typically exhibiting indolent growth, with limited potential for malignant transformation. Cutaneous meningiomas are rarely encountered, as direct extension of intracranial extension or metastasis of intracranial meningioma, or alternatively, as primary cutaneous disease. A 56 year-old woman diagnosed with left frontal lobe meningioma in 2003 and underwent intracranial extirpation. She presented to dermatology in March 2018 with 4 facial masses interpreted in referral as “enlarging facial cysts.” Partial excision revealed a glistening white tumor from the glabella. Histopathology showed a poorly circumscribed, bulbous silhouette with epithelioid and plasmacytoid cells associated with pleomorphism and zonal necrosis. Immunophenotyping revealed EMA, p63, and ERG expressions. Tumor was identified in bilateral frontal lobes, skull, orbits, and sinuses on Brain MRI. A diagnosis of recurrent atypical meningioma WHO Grade II was rendered. Although rarely encountered in dermatology, co-expression of p63/ERG can be a clue to cutaneous meningioma; additional history or ancillary studies (eg, Brain MRI) can help clinch diagnosis.

An Unusual Case of Renal Cell Carcinoma Presenting in the Skin by Direct Extension at Laparoscopic Port Site

Sarah E. Gradecki, MD and Alejandro A. Gru, MD

Department of Pathology, University of Virginia, Charlottesville, VA.

Although renal cell carcinoma (RCC) is known for its propensity to metastasize widely throughout the body, cutaneous metastases are uncommon and are seen in less than 3% of RCCs. A 55-year-old man presented with a painful red lesion with satellite nodules on his abdomen at a laparoscopic port site from a partial nephrectomy for a pT1a clear cell RCC that was performed 28 months prior. The lesion was excised; however, after excision the lesion recurred with continued pain and drainage from the surgical site, which was treated with multiple courses of antibiotics. Due to the persistent nature of the lesion, it was re-biopsied, and an atypical, keratin-positive, spindle-cell proliferation was identified within the dermis. The patient’s previous skin excision was reexamined, and the same atypical cells were identified within large areas of necrosis, granulation tissue, and fibrosis. Further workup was performed on the initial excision, and the atypical cells showed expression of CD10, CAIX, PAX 8, EMA, and vimentin, consistent with cutaneous involvement by RCC.

Linear IgA Bullous Dermatosis Presenting as Nasal Pruritus

Jennifer Gregory, MD and Nicholas Logemann, DO

Walter Reed National Military Medical Center, Bethesda, MD.

Sixty-two year old African American female with 1 year history of pruritic, clear vesicles which occur sporadically on face, neck, upper back and chest, along with gingival erosions. Her first symptom intranasal pruritus, for which she had received ENT surgical treatment due to chronic excoriations and difficulty with healing. Her past medical history includes osteoarthritis and hypertension, and her medications included meloxicam, ibuprofen and losartan. Biopsy of an erythematous papule with H&E staining was suspicious for a subepidermal immunobullous dermatitis. Biopsy for direct immunofluorescence obtained from an intact vesicle on the left earlobe was consistent with linear IgA bullous dermatosis (LABD). Since discontinuing ibuprofen and meloxicam, which are reported causes of drug-induced LABD, she reports significantly decreased frequency and faster resolution of new gingival lesions. LABD may occur on mucous membranes, which may be more symptomatic than classic cutaneous lesions. Additionally, this case is unique in that the patient’s initial symptoms were intranasal pruritus and small vesicles, which have not recurred since beginning treatment and discontinuation of NSAIDs.

Skin Ulcers: A Solely Manefestation of Hypereosinophilic Syndrome (Case Report)

Yasmin Hambaroush, MD, Fernando De Castro, MD, and Shadi Qasem, MD

Department of Pathology, University of Kentucky, Lexington, KY.

Idiopathic hypereosinophilic syndrome (HES) is a rare disorder characterized by persistently elevated absolute eosinophil counts without any underlying cause. Depending on the organ involved; the presenting complaint can vary. The most common involved organs are the skin, lungs, digestive tract, heart, blood and nervous system. We hereby report a case of HES presenting solely with skin ulcers only and no other organs involvement. Thirty years old female with a history of painful, itchy, variable size skin ulcers on the back, arms, axillae, and forehead for 1 year. Lesions progressed over the past year to cover significant areas of her body despite being treated with high doses of corticosteroids. Histopathology revealed ulceration with eosinophil rich dermatitis and focal granulomatous inflammation with no vasculitis. Lab results include positive ANA, consistently elevated absolute eosinophils count, IL5, CRP, platelets, and anemia. Based on HES diagnosis criteria (Eosinophil counts >1.5 × 109/L for ≥6 months, lack of evidence for parasitic, allergic, or other recognized causes of eosinophilia, symptoms and signs of organ system involvement), patient met criteria for the diagnosis of HES in the setting of cutaneous involvement as the sole manifestation of this rare disease. FIP1L1-PDGFRA gene analysis is pending. Patient is responding to treatment with anti IL-5 treatment.

Regressing Melanocyic Nevi in Anti-PD-1 Treatment of Melanoma

Emily Hartsough and Daniel Miller, MD

University of Minnesota, Minneapolis, MN.

Objective: Programmed death receptor 1 (PD-1) inhibitors are becoming the new standard of care for advanced melanoma, with dermatologic toxicities among their most common side effects. Here, we add to a growing number of reports describing the novel phenomenon of PD-1 inhibitor-mediated melanocytic regression.

Methods: We reviewed clinical charts and pathologic interpretations of 2 patients at our institution with melanocytic nevi undergoing inflammatory regression following treatment with PD-1 inhibition.

Results: Patient 1 had stage IV melanoma and synchronously developed 2 nonpigmented domed papules on the parietal scalp following 7 rounds of pembrolizumab; biopsies of each demonstrated intradermal nevi without significant atypia but with inflammatory regression. Patient 2 received nivolumab for treatment of BRAF V600E-mutated, stage IIIB melanoma and also subsequently presented with a new-onset domed, flesh-toned papule on the forearm, with histopathology demonstrating a bland intradermal melanocytic proliferation with lymphocyte-mediated regression resembling a halo reaction.

Conclusions: Regression of melanocytic nevi is an emerging side effect of anti-PD-1 treatment of melanoma and may lead to atypical clinical changes in existing nevi, as well as misleading histopathologic findings when this phenomenon is unrecognized.

Keloidal Variant of Atypical Fibroxanthoma

Hannah Hill, Steven Nelson, and David J. Dicaudo

Mayo Clinic, Scottsdale, AZ.

An 82 year old male presented with a tender, rapidly-growing nodule on the helix of the left ear. Shave biopsy revealed a dense infiltrate of atypical spindled and epithelioid cells with pleomorphic nuclei and numerous mitotic figures. Atypical cells were found to encircle keloidal collagen bundles. Negative stains performed included CK5/6, CK 903, MART-1, SOX10 and S-100. The tumor was diagnosed as atypical fibroxanthoma (AFX), keloidal variant and subsequently treated with Mohs micrographic surgery. Our case is clinically characteristic of AFX, occurring on the head of an elderly person in a sun-exposed location. The keloidal variant is considered a distinct and under-recognized histologic variant of AFX. Keloidal collagen is believed to be a product of the tumor cells and not simply stromal reaction. Differentiation from benign entities is important as keloidal collagen can occur in entities such as dermatofibroma and scar. Recognition and appropriate classification of the atypical spindle cell infiltrate continues to be essential to the diagnosis to rule out leiomyosarcoma, malignant melanoma and spindle cell squamous cell carcinoma.

Pediatric Pigmented Epithelioid Melanocytoma of the Scalp With NKTR3 Gene Rearrangement

Ben J. Friedman (senior author)* and Angela Jiang (presenter)†

*Department of Dermatology, Department of Pathology and Laboratory Medicine, Henry Ford Health System; and †Resident in Dermatology, Henry Ford Health System, Detroit, MI.

A 4 year-old African American female presented to our clinic with a 2-month history of a growing nodule on her right parietal scalp. Clinical examination revealed an ∼ 3 × 3 cm skin colored subcutaneous nodule with a very small focus of superficial pigmentation. A 4 mm punch biopsy from within the nodule was obtained for histopathological analysis. On gross exam the dermis and subcutis appeared homogenously black. Microscopic analysis revealed nodular aggregations of heavily melanized epithelioid melanocytes throughout the dermis and subcutis with a mitotic rate of ∼ 1 per mm2. Cytologically the cells were medium-sized and demonstrated modestly pleomorphic vesicular nuclei with prominent nucleoli. The neoplasm was sent for array CGH testing and was found to have chromosomal gains and losses in 15q and gains in 17q, consistent with borderline lesion without characteristic anomalies seen in melanoma. Additionally, a breakpoint was detected within the NKTR3 gene suggestive of a rearrangement. Complete re-excision of the entire neoplasm revealed identical morphological findings. Overall, the features in this case were consistent with a diagnosis pigmented epithelioid melanocytoma (PEM). The presence of an NKTR3 rearrangement in this case adds to the potential characteristic genomic alterations that have been recently described in this entity.

A Rare Case of Intralymphatic Histiocytosis Following Surgical Placement of Orthopedic Prosthesis

Emma Johnson,* Ashley Wentworth,* John Muzic,* and Julia Lehman*,†

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

Introduction: Intralymphatic histiocytosis is a rare, reactive cutaneous process characterized by the presence of dilated lymphatic channels containing aggregates of histiocytes within the lumina. The clinical presentation varies widely and may mimic that of vascular neoplasms.

Case: A healthy 60-year-old male with a history of bilateral knee prostheses and chronic right leg lymphedema presented for evaluation of a mildly pruritic eruption on the right shin. Examination revealed a red-to-purple, indurated, reticulated, vascular appearing plaque. Differential diagnosis at the time was broad, including vasculitis, vascular neoplasm, erythema ab igne, and lichen planus. Incisional biopsy and immunohistochemistry demonstrated proliferation and dilation of lymphatic channels with intraluminal clusters of histiocytes, confirming the diagnosis of intralymphatic histiocytosis.

Discussion: Intralymphatic histiocytosis represents an unusual and infrequently encountered reactive process of unknown pathogenesis. It is associated with inflammatory processes (rheumatoid arthritis, diabetes, malignancy) and/or lymphedema. Immunohistochemical staining of dilated lumina with vascular and lymphatic markers may confirm diagnosis. This case highlights the importance of recognizing intralymphatic histiocytosis, particularly in certain clinical settings.

Well-Differentiated Neuroendocrine Carcinoma of the Skin

Jeptha T. Johnson, MD* and Michael C. Royer, MD†

*Walter Reed National Military Medical Center, Bethesda MD; and †Joint Pathology Center, Silver Spring, MD.

Well-differentiated neuroendocrine carcinomas (NECs) are rare tumors of the skin, most commonly arising through metastasis from the gastrointestinal tract or lungs. They may rarely occur as primary tumors of the skin. Diagnosing these tumors may be difficult, with the primary differential including Merkel cell carcinomas and adnexal neoplasms. We report the case of an 81-year-old man with no past medical history of NEC who presented with a pink-tan nodule on his left parietal scalp. Histology reveals a well-circumscribed dermal tumor with moderately sized cells in cords, nests and focal rosettes with granular chromatin and scattered mitoses. Immunohistochemical stains for synaptophysin, chromogranin and CD56 are positive. EMA, p63, TTF-1 and PSA are negative. The findings are consistent with a well-differentiated NEC. Dermatopathologist awareness of these rare tumors is important, as they may be misdiagnosed as primary cutaneous adnexal neoplasms or Merkel cell carcinomas. Additionally, identification of a cutaneous carcinoid tumor necessitates thorough investigation for a primary carcinoid tumor with CT scans of chest and abdomen, enteroscopy and potentially bronchoscopy.

Squamous Metaplasia of Lactiferous Ducts

Jeptha Johnson, MD and Nicholas Logemann, DO

*Walter Reed National Military Medical Center, Bethesda, MD.

Squamous metaplasia of lactiferous ducts (SMOLD) is an uncommon condition in which squamous epithelium of the breast extends more deeply into the nipple duct orifice. SMOLD frequently presents as recurrent subareolar abscesses, often resulting in repeat incision and drainage when incorrectly diagnosed. We report the case of a 22-year-old woman who presented to her dermatologist with a 6-month history of a 4 mm, non-tender, mobile mass on her left areola. Ultrasound evaluation was performed to rule out carcinoma and the findings were consistent with epidermal inclusion cyst versus scar. The patient was referred to general surgery for excision. Histology demonstrates lactiferous ducts with extensive squamous metaplasia, and collection of desquamated keratinocytes consistent with squamous metaplasia of lactiferous ducts. Dermatopathologist awareness of this uncommon condition is crucial as it may mimic recurrent abscesses and patients may undergo multiple incisions and drainages prior to receiving definitive treatment with excision of the duct. With this case report we hope to raise awareness of this condition and facilitate increased pathologist and clinician recognition.

Verruciform Amyloidosis: A Distinctive Morphologic Variant of Localized Cutaneous Amyloidosis

Julio A. Diaz-Perez, Muhammad Ahmad, Harry M. Goldin, Thomas L. Cibull, and Amandeep Kaur

NorthShore University HealthSystem, Evanston, IL.

Amyloidosis is caused by the extracellular deposition of protein as beta-pleated sheets which appears as amorphous eosinophilic material by H&E and demonstrates characteristic apple green birefringence with Congo Red. Previously described variants of localized cutaneous amyloidosis (LCA) include: macular, lichenoid, nodular, poikiloderma-like, cutis dyschrornica, and bullous amyloidosis. LCA is subdivided into primary and secondary types. In the primary type of LCA the amyloid is derived from keratin and will demonstrate positivity with cytokeratin (34ßE12) by IHC. The purpose of this case study is to propose a new variant of primary LCA: verruciform amyloidosis. Our patient is a 75-year-old male presenting with a scrotal verruciform lesion. Result: Histopathologic sections demonstrated marked hyperkeratosis and acanthotic verrucous epidermis, with abundant dyskeratotic cells, and amorphous eosinophilic material in the papillary dermis. This material demonstrated apple green birefringence under polarized light with Congo Red stain and cytokeratin 34ßE12-positivity. There was no evidence of squamous dysplasia, viral changes, or mycotic infection. We propose the name verruciform amyloidosis for this morphologic variant of primary LCA, which demonstrates a verrucous appearance. The correct identification of this variant of LCA is relevant when considering other verruciform lesions in the genitals.

Wart-Like Inverted Follicular Keratosis With Sebaceous Differentiation

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

Department of Pathology, NorthShore University HealthSystem, Evanston, IL.

Inverted follicular keratosis (IFK) is a benign tumor of the follicular infundibulum which some consider as a variant of seborrheic keratosis. IFK most commonly occurs on head and neck, especially cheeks and upper lip. Various variants of IFK have been identified which include: wart-like, keratoacanthoma-like, solid nodular form and cystic type. We present a wart-like IFK with sebaceous differentiation. A 71 year-old-female presented with a right parietal scalp lesion measuring 2 cm. Histopathologic examination demonstrated a verrucous to inverted appearing keratinocytic proliferation with hyperkeratosis and parakeratosis forming a horn. The epidermis was acanthotic with prominence of the granular cell layer and there were innumerable squamous eddies. Additionally, throughout the keratinocytic proliferation arising from the epidermis were aggregates of basaloid cells with admixed mature appearing sebaceous cells. There was no cytologic atypia or evidence of an infiltrative growth pattern. There was no evidence of microsatellite instability. With these findings, a diagnosis of wart-like IFK with sebaceous differentiation was rendered. To our knowledge, this is the first report of a wart-like IFK with sebaceous differentiation.

Interstitial Granulomatous Primary Cutaneous Marginal Zone Lymphoma (PCMZL): A Morphologic Variant

Amandeep Kaur, Julio A. Diaz-Perez, and Thomas L. Cibull

Department of Pathology, NorthShore University HealthSystem, Evanston, IL.

Primary cutaneous marginal zone lymphoma (PCMZL) presents as solitary or multiple papules on trunk with an indolent behavior. PCMZL demonstrates a nodular or diffuse mononuclear infiltrate with sparing of epidermis. The infiltrate is composed B-cells, plasma cells and admixed reactive T-cells with variable formation of germinal centers. Unusual histologic variants have been documented including: panniculitis-like, epidermotropic, and with amyloid deposition. The objective of this study is to describe the interstitial granulomatous (IG) variant of PCMZL which has not been previously reported. A 70 year old male presented with annular patches and plaques on flank and arms, clinically resembling granuloma annulare (GA). Histopathologic findings demonstrated peri-vascular to nodular lymphoplasmacytic infiltrate with monotypic light chain restriction. There were interstitial histiocytes and multinucleated giant cells, some of which demonstrated elastophagocytosis. The diagnosis of PCMZL with IG features was rendered. The differential diagnosis for IG reaction pattern is broad including GA, IG dermatitis secondary to systemic illness, drug reaction, or T-cell lymphoma. The IG variant of PCMZL should be considered in the differential diagnosis of IG lesions.

A Case of Hypertrophic Discoid Lupus Erythematosus of the Vulva Mimicking Lichen Simplex Chronicus

Kathleen Kelley, MD, Dena Elkeeb, MD, MS, and Oluwakemi Onajin, MD

Section of Dermatology, University of Chicago, Chicago, IL.

Discoid lupus erythematosus (DLE) rarely affects the genital mucosa. To date, there have been 10 previously reported cases in the literature. We present a case of hypertrophic DLE of the vulva mimicking lichen simplex chronicus. A 66-year old African-American female with a past medical history of generalized DLE presented with a 2-year history of painful and pruritic vulvar lesions. She was previously diagnosed with lichen simplex chronicus of the vulva. Physical examination revealed pink, depigmented, hyperkeratotic plaques with focal erosions involving the clitoral hood and anterior labia majora. A punch biopsy demonstrated epidermal hyperplasia with hyperkeratosis and hypergranulosis, lichenoid interface dermatitis, and a dense superficial perivascular and periadnexal lymphocytic infiltrate. Periodic acid-Schiff and colloidal iron stains demonstrated basement membrane thickening and increased dermal mucin, respectively. The patient was diagnosed with hypertrophic discoid lupus erythematosus of the vulva. We present this interesting case to highlight a rare manifestation of discoid lupus erythematosus. Accurate diagnosis of DLE involving the genitalia requires a high degree of clinical suspicion by dermatologists and dermatopathologists.

Histopathologic Features of Riehl’s Melanosis

So Min Kim, Eun-So Lee, and You Chan Kim

Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.

Histological features of Riehl’s melanosis have rarely been compared between lesional and perilesional normal skin, and have not been described by quantitative or immunohistochemical analysis. To investigate the histopathological features of lesional and perilesional skin, and to compare them using immunohistochemical staining, we retrospectively evaluated the biopsy specimens of 48 patients. Hematoxylin and eosin stain, Fontana-Masson stain and other immunohistochemical stainings were performed including Melan-A, NKI/beteb, and microphthalmia-associated transcription factor. Increased pigments were observed in the dermis of lesional skin. Although the difference was statistically insignificant, melanin pigment was increased in lesional epidermis. The number of melanocytes and their activity were significantly increased in lesional epidermis. Although the severity was lower, pigmentary incontinence, basal cell liquefaction, dilated vessels, colloid bodies were found not only in the lesion but also in the perilesional normal skin. Riehl’s melanosis is a disease of increased epidermal melanocytes and increased pigmentation in both epidermis and dermis, along with a histologically typical interface change. Unlike other pigmentary diseases, it's noteworthy that a large number of asymptomatic perilesional skin also have typical histopathologic changes.

Dermatofibrosarcoma Protuberans (DFSP) Arising in Association With Cellular Dermatofibroma (DF)- Coincidence Or Causation?

Sarah King,* Neil Coleman,† Robert Page,† and Roy King†

*ETSU Medical School, Johnson City; and †Dermatopathology Partners, and University of Tennessee, Department of Pathology, Knoxville, TN.

DFs are benign fibrohistiocytic dermal lesions whereas DFSPs are low-intermediate grade sarcomas that widely infiltrate the subcutis. The 2 entities are usually distinguishable histologically and immunohistochemically, but may be diagnostically challenging. Twenty-eight y/o female presented with a 9 month h/o growing lesion on her left thigh, clinically thought to represent a cyst. The biopsy demonstrated a cellular dermal proliferation comprising of a mix of fibroblastic, myofibroblastic and histiocytic cells consistent with DF. Extending deep from this proliferation was a uniform spindled proliferation with a storiform growth pattern widely involving the subcutis (honeycomb pattern). Immunohistochemically the DF was FXIII a+/CD34−, desmin−, and the DFSP CD34+, desmin+/FXIIIa−. Intermediate fibrohistiocytic lesions of the skin with overlapping features of DF and DFSP have been reported with cases demonstrating cellular fibrohistiocytic lesions and CD34+/FXIIIa+. None of these cases demonstrated 2 distinct histologic and immunophenotypic proliferations. To the best of our knowledge this is the first reported case of a DFSP arising in association with a cellular DF. Given the common occurrence of DFs this may represent an incidental finding. In superficial biopsies of cellular DFs, re-excision should be considered.

Primary Cutaneous Cribriform Carcinoma: A Rare Cutaneous Adnexal Neoplasm

Katelen Korty, DO, Lin Wang, MD, and Melissa Piliang, MD

Cleveland Clinic, Cleveland, OH.

Primary cutaneous cribriform carcinoma (PCCC) is a rare sweat gland tumor typically on the extremities of middle-aged women. It has been characterized as having an excellent prognosis without metastasis. Clinically, they present with bland features; as slow growing solitary subcutaneous nodules and may resemble dermatofibroma or inflamed epidermal inclusion cyst. We present a case of a 69-year-old female who presented with a dome shaped pink-tan nodule located on her right proximal calf. Histologic sections revealed a relatively well-demarcated tumor. There were multiple interconnected solid cystic elements forming a cribriform/glandular pattern embedded in fibrotic stroma. The lesional cells displayed cuboidal to oval shaped nuclei with hyperchromasia and mild pleomorphism within scant eosinophilic cytoplasm. The tumor cells were positive for cytokeratin 7, cytokeratin 5/6 and S-100. Negative stains included CD31, cytokeratin 20, CD34, and SMA. EMA and CEA highlighted the lumens of the glandular proliferation. These combined histologic and immunophenotypic findings were consistent with PCCC and complete excision was recommended. Other entities to consider in the differential diagnosis include: adenoid cystic carcinoma, primary cutaneous secretory carcinoma and metastatic carcinoma.

Calcinosis Cutis Due to Strensiq Injections

Stephanie Liu, DO, MBA and Robert Phelps, MD

Department of Dermatopathology, Icahn School of Medicine at Mount Sinai, New York, NY.

Strensiq (asfotase alfa) is a subcutaneous injection approved to treat infantile and juvenile onset hypophosphatasia (HPP). HPP is a rare genetic metabolic condition seen in mutations of the tissue nonspecific alkaline phosphatase (TNSALP) gene, and inheritance can be autosomal dominant or recessive. Patients experience abnormalities of mineralization, leading to bone fractures and tooth loss. Strensiq, introduced in 2015, is the first FDA approved treatment for HPP. The mechanism of action involves targeting and replacing the TNSALP gene. Our patient was a 36 year old female with a past medical history of HPP, systemic lupus erythematosus, and stroke, who developed a nodular injection site reaction in the thigh after receiving Strensiq injections. Clinically, the lesions resembled psoriasis, but were concerning for vasculitis or panniculitis. Histologic examination revealed a histiocytic reaction with fat necrosis and calcinosis cutis. Small calcific globules were dispersed through the collagen bundles in the mid to deep dermis. The globules were positive on Von Kossa immunohistochemical stain. To our knowledge, this is the first reported skin biopsy with findings related to Strensiq injections.

Acknowledgements: Robin Blum, MD.

KI67 Staining Pattern in Seborrheic Keratoses

Y. A. Liu and R. I. Crawford

University of British Columbia, Vancouver, BC, Canada.

Background: Seborrheic keratoses (SKs) are common benign skin tumours that arise in non-volar skin of older individuals. When arising in the genital region, they can be difficult to distinguish from condyloma acuminatum (CA). Abnormal Ki67 immunohistochemical staining of cells in the superficial epidermis has been reported to be associated with HPV detection in CA. Our study aims to characterize Ki67 staining patterns of SK versus CA staining patterns across all body sites.

Methods: We identified 12 patients with genital and non-genital SKs and 5 patients with genital and non-genital condylomata. We defined an abnormal result as Ki67 staining in the superficial half of the epidermis and increased nuclear size of the positively staining nuclei.

Results: Four cases of condyloma and 3 cases of SK from the head and neck region demonstrated abnormal Ki67 staining. Four cases of non-genital SKs showed Ki67 staining in the superficial epidermis, but the positive-staining nuclei were not enlarged.

Conclusions: Non-genital SKs can demonstrate a pattern of Ki67 staining that would suggest a diagnosis of condyloma. Strict criteria and caution should be used when interpreting Ki67 staining for this purpose.

Malignant Atrophic Papulosis Presenting With Bilateral Upper and Lower Extremity Lesions

Lisa M. Marinelli, BS,* Kabeer K. Shah, DO,* Robert Anderson, MD, PhD,† Andrea Conway, MD,† and Michael Camilleri, MD†

*Mayo Clinic, Rochester, MN; and †Dermatology Consultants, St. Paul, MN.

Degos disease, or malignant atrophic papulosis (MAP), represents an extremely rare cause of dermal papular lesions which can herald a fatal clinical outcome. A 37-year old female with a history of non-metastatic melanoma skin cancer, presented with a 1 month history of erythematous papules involving the bilateral upper and lower extremities. At presentation, the lesions evolved into white papules and macules with a rim of peripheral erythema, measuring 5–7 mm in diameter. Biopsy demonstrated epidermal atrophy overlying a wedge shaped area of dermal fibrosis, with deep dermal thrombotic microangiopathy, consistent with a diagnosis of MAP. Clinical and histopathologic recognition of MAP should be made for appropriate systemic workup in patients presenting with characteristic lesions. Systemic workup includes consideration of gastrointestinal, CNS, pulmonary, ophthalmologic, and cardiac involvement by thrombo-obliterative vascular lesions. It is important to distinguish between the benign cutaneous variant and the systemic, fatal variant of this disease which portends a 50% 5-year survival.

Wells Syndrome Associated With Lymphangitis

Haider Mejbel,* Johanna Preiszner,* M. Salah Shurbaji,* Stuart Leicht,† and George Youngberg*

Departments of *Pathology and †Dermatology, East Tennessee State University.

We are reporting a case of a 61 year-old white male who presented with 3 distinct skin lesions, including an erythematous plaque, a blister and a painful linear streak on his left anterior thigh, left posterior wrist, and left anterior forearm, respectively. Histopathological examination of punch biopsies of the 3 lesions revealed skin with a diffuse interstitial eosinophilic infiltrate predominantly involved the dermis. However, Flame figures were not readily identified. A Luna stain highlighted the degranulating eosinophils and “flame figures” supporting the diagnosis of Wells Syndrome. To our knowledge, this is the first case of Wells syndrome presenting in association with lymphangitis. In addition, this case is a perfect demonstration of the use of the Luna stain as a simple and cost-effective method to detect equivocal flame figures, serving as a helpful confirmatory tool in the diagnosis of unusual cases of Wells syndrome. Finally, lymphangitis may represent a sign of systemic involvement which may require an extended course of treatment regardless of the extent of the primary skin disorder.

ALK Expression in Merkel Cell Carcinoma. An Immunohistochemistry Study in 210 Cases

María Dolores Mendoza-Cembranos,* Carlos Santonja,† Victoria Alegría-Landa,* Miguel Ángel Piris,† Heinz Kutzner,‡ and Luis Requena*

Departments of *Dermatology and †Pathology, Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain; and ‡Dermatopathologie Laboratory, Friedrichshafen, Germany.

Winner of Best Poster.

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor that has been implicated in the pathogenesis of a variety of neoplasms. We conducted a study examining the presence of ALK in Merkel cell carcinomas (MCC). A total of 210 cases of MCC were analyzed. Immunohistochemistry was performed using the clone D5F3 of the ALK antibody. ALK reactivity was observed in 90.9% (191/210) of cases. From negative cases, 84.2% (16/19) of them were also negative for MCCPolyomavirus (MCCPyV). The immunohistochemical characterization of ALK in MCC allows us to propose new etiopathogenic theories as well as the possibility of using target inhibitors as an alternative treatment.

Langerhans Cell Histiocytosis and Multiple Reticulohistiocytomas in a Patient With TAR Syndrome a Non-previously Described Association

C. Menicanti,* L. Nuñez Hipólito,† L. Prieto Torres,† V. Alegría-Landa,† and L. Requena†

*IRCCS Cà Granda Foundation, Dermatology Unit, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; and †Department of Dermatology, Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain.

Histiocytoses comprise a heterogeneous group of disorders characterized by proliferation of cells thought to be derived from monocytes, macrophages and dendritic cells in different organs. Langerhans cell histiocytosis (LCH) is a rare dendritic cell condition occurring mainly in pediatric population. LCH frequently presents as a multi-systemic disease, being the skin the second most common involved organ. LCH belongs to the L-group of histiocytosis and mutations in the Ras/Raf/MEK/ERK pathway have been proposed as the underlying pathogenic mechanism. On the other hand, reticulohistiocytoma (RH) is a benign dermal tumor, usually found as a solitary lesion limited to the skin. RH belongs to the C-group of histiocytosis and is considered a reactive process. We present a young woman with thrombocytopenia and bilateral radius agenesis, condition known as TAR syndrome, multisystemic LCH and multiple RHs. To the best of our knowledge, there is no previous description of such infrequent association in the literature.

Comprehensive Histopathological Study of Malignant Melanoma With Immunohistochemical Analysis—Study From Tertiary Care Cancer Center

Mitul B. Modi, MD,* Jigisha Chadhari, MD,† Vipulkumar Prajapati, MD,‡ and Irappa Madabhavi, MD, DM§

*PGY2, Resident Physician, Department of Pathology, Pennsylvania hospital of University of Pennsylvania health system, Philadelphia, PA and Department of Pathology, Gujarat Cancer & Research Institute, Ahmedabad, Gujarat, India (Presenter, not sponsored); †Resident Physician, Department of Pathology, Baroda Medical College, Vadodara, Gujarat, India; ‡Assistant Professor, Department of Anatomy, B. J. Medical College, Ahmedabad, Gujarat, India; and §Fellow, Department of Medical Oncology, Gujarat Cancer & Research Institute, Ahmedabad, Gujarat, India.

Objective: The aim of our study is to reveal about histomorphology and immunohistochemical analysis of malignant melanoma after careful clinical correlation.

Methods: We conducted retrospective study at tertiary care center. The hundreds patients of malignant melanoma (2012–2016) were identified and clinical and radiological details data were retrieved from casefiles. Immunohistochemical stains of melanoma panel, consisting of S- 100, Melan-A, HMB-45 was performed on formalin fixed paraffin embedded section from each case with antigen epitope enhancement by heat.

Results: Patients in our study belonged to the age group in range of 22–84 years, with mean age being 53.57 years and a sex ratio of 1.7:1. The foot was most common site for and liver was least common site of melanoma. Our study showed superficial spreading melanoma (n = 63), nodular melanoma (n = 25), acral lentiginous melanoma (n = 10) and lentigo maligna melanoma (n = 2). Our study showed frequent metastasis in regional lymphnodes (22%) and infrequent distant metastasis (liver and brain).

Conclusions: Our study shows 100% positivity for vimentin, S-100, HMB-45 and negativity for AE1-3, EMA, LCA, which supports the histologic diagnosis. Because melanoma evolve over time from localized skin lesions to aggressive tumors, early recognition is important.

Onycholemmal Carcinoma; Two Cases With Literature Review

Adnan Mubasher, MD, Tauhid Awan, MD, Mohammad Qazi, MD, and Rajendra Singh, MD

Mount Sinai Health System, New York.

Background: Onycholemmal carcinoma (OC) is a rare entity that is thought to be of nail-bed epithelium origin. It is a slow growing tumor of elderly and is often misdiagnosed. The clinical presentation varies and may mimic trauma-induced onychodystrophy, onycholemmal cyst or onychomycosis or it may resemble a squamous cell carcinoma, verrucous carcinoma, Bowen’s disease or subungual keratoacanthoma. Only 13 cases have been reported in the English literature so far.

Design: We herein describe clinical and histological features of 2 cases of Onycholemmal carcinoma.

Results: A 69 year-old-male presented with a 1.5 × 0.8 cm ulcerated lesion on right thumb involving the nail; the second patient was a 48 year-old female who complained of painful ingrown nail of the left hallux. Both patients underwent resection of the lesion. Histological examination revealed dermal nested growth pattern of squamous epithelium in the background of sclerotic stroma and areas of abrupt onycholemmal keratinization. Small cysts with keratinization in the absence of granular layer were also observed. Sparse melanocytes were highlighted with Melan-A while p16 staining was negative in the epithelium.

Conclusions: Although considered to be a disease of the elderly, OC should be considered in the differential diagnosis for young patients as well, especially given the aggressive behavior and malignant potential. Currently available treatment modalities include Mohs micrographic surgery, conservative excision, debridement of the nail apparatus and amputation, if needed. Aggressive approach is recommended given the malignant potential of these lesions.

Neurothekeoma Multiplicity—A Multiply Occurring and Recurrent Case of a Rare Entity

David J. Myers, Ryan A. Collins, and Kevin J. Krauland

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

We present a case of 2 cellular neurothekeomas occurring simultaneously on the same individual 2 years after he had a solitary neurothekeoma excised. One lesion was excised from the patient’s cheek, and one from the patient’s nasal bridge (which was the site of the original excision 2 years prior). There are only a handful of reported cases of neurothekeomas occurring in a non-solitary form. Neurothekeomas are rare benign dermatologic lesions, with the first known case of multiply occurring neurothekeomas published in 2006. Cellular neurothekeomas are soft cutaneous papules or nodules which are characterized by a dermal proliferation of spindled or epithelioid cells in nests and/or fascicles. There are varying amounts of sclerotic stroma present. These lesions may histologically resemble melanocytic lesions, therefore immunohistochemistry is an important diagnostic tool to confirm the diagnosis. In the current case, both lesions showed similar morphology and staining patterns, with positivity for MiTF and CD10, and negativity for pan-keratin, MART-1, and SOX10. This case presents one of a rare few reports of multiply occurring neurothekeomas, comparison of a primary lesion with a recurrent lesion, as well as providing a brief review of their histology and immunohistochemical staining pattern.

Primary Systemic Amyloidosis—A Subtle Deposition Pattern

Heather O’Connor, DO, John Metcalf, MD, and Jessica Forcucci, MD

Medical University of South Carolina, Charleston, SC.

Primary systemic (AL) amyloidosis is a rare disease that results in deposition of insoluble extracellular monoclonal immunoglobulin light chains. Clinically unremarkable skin is involved in 50% of cases, making abdominal fat pad biopsy a minimally invasive diagnostic modality; however, few biopsies yield significant findings. In the few positive biopsies, amyloid is typically identified within the dermis and subcutis. We report a case of sparse superficial perivascular dermal amyloid deposition, confirmed by mass spectrometry, emphasizing the importance of thorough examination and histochemical stains. A 48-year-old male was admitted for polyendocrinopathies and infiltrative cardiomyopathy, warranting a workup for systemic amyloidosis. H&E stained slides of an abdominal fat pad biopsy were initially unremarkable; however, multiple amyloid stains demonstrated scant amounts of perivascular amyloid within the superficial dermis, sparing the deep dermis and subcutis. Despite the diagnosis, the patient rapidly deteriorated and died secondary to complications. This case emphasizes the utility of skin biopsies for systemic amyloidosis and emphasizes the importance of careful specimen evaluation and the use of histochemical stains to detect subtle amyloid deposition.

A Histologic Analysis of 90 Merkel Cell Carcinomas

Toru Ogawa, MD and Mai P. Hoang, MD

Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA.

Introduction: Merkel cell carcinoma (MCC) is a rare and high aggressive neuroendocrine carcinoma with unknown origin.

Objective: To determine the frequency of various unusual morphologic appearance of MCC.

Design: A retrospective histologic review from 1997 to 2018 was performed.

Results: Of the 90 primary MCC identified, intraepidermal carcinoma or epidermotropism was noted in 8/90 (9%) cases. An association with pilar cyst was noted in 1/90 (1%), with actinic keratosis (AK) in 2/90 (2%), with squamous cell carcinoma (SCC) in situ and invasive in 7/90 (8%), and with basal cell carcinoma (BCC) in 1/90 (1%) cases. There was 1 case of metastatic MCC in a lymph node with chronic lymphocytic leukemia (CLL) and 1 case of metastatic MCC and SCC in a lymph node.

Conclusions: MCC can rarely associated with follicular cyst. The association of MCC with SCC and BCC, noted here and in the literature, supports the role of ultraviolet light as an etiologic agent. Although rare, the association with CLL confirms the role of immunosuppression in the pathogenesis of MCC.

Foreign Body Granulomatous Reaction by Permanent Filling Material

Jana Quezada Almonte, Felix Padilla, Bertha Saleta, Edel Gomez, Juan Pablo Guzman, Angel Taveras, and Raisa Acosta

Dominican, Republic.

The granulomatous reaction to a foreign body has been described since the last century, but the rise of aesthetic procedures without adequate supervision, even worse, practiced by unqualified personnel, as well as the performance of such procedures in detrimental sanitary conditions, makes foreign body granulomas more common in typical localizations. We report the case of a 34-years-old female patient, Fitzpatrick’s photo type IV, Dominican, which came to our institution because of a painful dermatosis that affects genitals of 6 months of evolution. Not relevant background. At the dermatological examination she presented deformed external genitals, aspect and configuration by bulging of the vulva, both of the mons pubis, the major and minor labia, of stony consistency, renitent at the expense of multiple indurated and fluctuating nodules, deep fissures and hyperpigmentation. Histopathology: Suppurative inflammatory process and granulomatous type foreign body. To the clinical-pathological correlation Findings may correspond to foreign body type reaction (history of previous material injection. Discussion: The mechanism of action of the granulomatous reaction is still unknown, although it has been suggested that an infection could cause a cross-immune reaction or a stimulation of a type IV hypersensibility. Due to the increase in the number of these cases and their difficult management, we consider these a case of interest for the international community since our patient showed satisfactory results.

A Challenging Case of Reticulate Hyperpigmentation Associated With R-CHOP

M. Rigi, C. Wang, L. Graham, P. Pavlidakey, and B. Elewski

University of Alabama, Birmingham, AL.

A 68 year old Asian man undergoing treatment with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) for diffuse large B-cell lymphoma presents with an acute asymptomatic eruption on the trunk and upper extremities characterized by numerous hyperpigmented flagellate and reticulate streaks with minimal scale. The eruption occurred after 2 cycles of chemotherapy. A skin biopsy showed subtle interface dermatitis with postinflammatory pigment alteration. No vasculitic or vasculopathic changes were observed, and eosinophils were absent. The patient continued treatment on R-CHOP without further progression of the eruption or development of other associated symptoms. The rash persisted even after completion of chemotherapy. Flagellate and reticulate hyperpigmentation is a rarely reported phenomenon associated with many chemotherapeutic agents including bleomycin, daunorubicin, paclitaxel, cyclophosphamide and fluorouracil. The cause of hyperpigmentation associated with these agents is not clear, and in most cases the discontinuation of the causative drug is not necessary. Common histologic features of these dermatoses include increased melanin in the basal layer of the epidermis and pigment incontinence, though interface dermatitis has been reported. Most likely culprit drugs in this case are doxorubicin and cyclophosphamide. The rash morphology in this case is distinct from the flagellate hyperpigmentation associated with bleomycin.


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2. Cohen, PR. Paclitaxel-associated reticulate hyperpigmentation: report and review of chemotherapy-induced reticulate hyperpigmentation. World J Clin Cases. 2016;4:390–400.

3. Baselga E, Drolet BA, Casper J, Esterly NB. Chemotherapy-Associated Supravenous Hyperpigmentation. Dermatology. 1996;192:384–385.

Angiocentric Diffuse Large B Cell Lymphoma an Unusual Presentation of Lymphoma Involving the Breast

Bethany Rohr, MD,* Jacqueline M. Junkins-Hopkins, MD,*,† and Xiaohong Zhang, MD†

Departments of *Dermatopathology and †Pathology, Geisinger, Danville, PA.

Background: Angiocentric diffuse large B cell lymphoma (DLBCL) is an uncommon form of lymphoma. We discuss a confounding clinical presentation of DLBCL.

Case Description: A 48-year old woman presented with a left breast lump with an overlying erythematous plaque. Breast imaging highlighted an abnormality, and skin biopsy revealed an angiocentric infiltrate of atypical large pleomorphic CD45+/CD20+/PAX-5+/BCL-2+/MUM1+ (focal) cells, consistent with angiocentric diffuse large B cell lymphoma. A subsequent left breast core biopsy showed MUM1+ DLBCL. PET CT showed FDG activity in the left breast and overlying skin surface, and also in subcutis of the distal right lower extremity. All lesions responded to chemotherapy for DLBCL.

Conclusions: Angiocentric DLBCL is rare. When it is primary cutaneous, it often presents as violaceous plaques. MUM-1 staining is associated with aggressive disease. We present an unusual case of DLBCL that showed angiocentric cutaneous involvement on skin biopsy, but also presented as a breast tumor on both imaging and core needle biopsy. DLBCL, leg type and breast lymphoma are discussed.

Solitary and Multiple Epidermolytic Acanthoma: A Study of 131 Cases

Simon F. Roy, MD,* Feras M. Ghazawi, MD, PhD,† Keith A. Choate, MD, PhD,‡ and Jennifer M. McNiff, MD‡

*Department of Pathology, University of Montréal, Montréal, QC, Canada; †Division of Dermatology, University of Ottawa, Ottawa, ON, Canada; and ‡Department of Dermatology, Yale University School of Medicine, New Haven, CT.

Epidermolytic acanthoma (EA) is a rare, benign acquired keratosis displaying epidermolytic hyperkeratosis. We retrospectively reviewed clinical and histopathologic features of 131 cases of EA. We also performed linear regression of yearly incidence rates to assess for possible under-reporting of this entity. We found 9.08 cases per 100,000 biopsy specimens per year and demonstrate significant decreasing incidence rates. Analysis of anatomical sites of EA demonstrated a more frequent genital location in men (39.1% of cases, as compared to 9.7% for women). Contrary to previous studies, lesions were most frequently single (91.7%) and the mean age of presentation was 57.8 years. In a recent national poll, fewer than 50% of responders recognized an image of EA, indicating that EA is underdiagnosed. This series highlights the demographic and clinical features to aid in recognition of EA as a distinct entity.

Acknowledgements: ASDP for its mentorship award to Simon F. Roy.

A Rare Case of Lichen Planus-Like Atopic Dermatitis Involving the Hands

Jasmine Saleh, MD, MPH,* Brooke Vasicek, MD,† Jeave Reserva, MD,† James Swan,† Jodi Speiser,* and Kumaran Mudaliar, MD*

*Department of Pathology, Loyola University Medical Center, Maywood, IL; and †Department of Dermatology, Loyola University Medical Center, Maywood, IL.

Lichen planus-like atopic dermatitis clinically mimics lichen planus and poses a diagnostic challenge. We report a case of a 55-year-old African American female who developed intensely pruritic papules and plaques on bilateral hands. Histological examination demonstrated acute spongiotic dermatitis with lymphocyte exocytosis into the epidermis. Taken together, a diagnosis of lichen planus-like atopic dermatitis was made. This case serves to highlight that lichen planus-like atopic dermatitis presents as spongiotic dermatitis with a lymphocytic process. Careful attention to the physical examination and histopathological findings will assist in making an appropriate diagnosis.

A “Cyst” Excision With Unexpected Dermal Myeloid Sarcoma

Maryam Sayah, MD, Shelly Stepenaskie, MD, and Hillary Elwood, MD

Department of Pathology, University of New Mexico School of Medicine.

Case: Sixty-five-year-old male, with no prior significant medical history, presented to a general surgeon for removal of a ∼5 cm dermal-based lesion on upper back, clinically assumed to be a cyst. The mass was removed surgically. Histopathology showed sheets of atypical, monotonous hematolymphoid cells splaying the collagen fibers of the dermis and extending into the subcutis. These cells are positive for CD43, CD45 (dim), CD33, CD68, CD34, MPO, Lysozyme, ERG (moderate intensity) and negative for CD138, CD117, CD3, CD20, Sox-10, Pancytokeratin. These changes are of a leukemia cutis (myeloid sarcoma) presenting as a solitary lesion in a patient without prior leukemia history. The patient was referred for additional work up. Follow-up labs were notable for significant pancytopenia. A bone marrow biopsy showed Acute Myeloid Leukemia (AML) with 22% blasts and FISH positive for MLL arrangement. Flow cytometry showed AML, 42% blasts, with monocytic differentiation. Patient was started on appropriate chemotherapeutic regimen.

Conclusions: Dermal myeloid sarcoma can present as a solitary dermal lesion, mimicking a cyst, and can precede the development of systemic AML.

Encapsulated Neurofibroma in an Otherwise Healthy Patient-Reactive Process or Rare Entity

CPT William Schaffenburg, MD* and Nicholas F. Logemann, DO†

*PGY3, Walter Reed National Military Medical Center, Bethesda, MD; and †Walter Red National Military Medical Center, Bethesda, MD.

A healthy 37 year-old male presented with a tender dermal nodule on the lower back, and requested removal. On surgical excision, a well encapsulated cystic structure was extirpated, showing a glistening white capsule. Histopathology showed an encapsulated dermal neoplasm of fragmented to elongated, fascicular, eosinophilic fibers with sparse cellularity interposed with myxoid stroma. No Antoni A or B bodies were seen, with spindled, elongated, ovoid, and round cells. There was mild to moderate pleomorphism and hyperchromasia, without atypical mitotic figures visible. There was strong staining with S100, and the capsule stained faintly positive with EMA and SMA. While a schwannoma was considered, given the lack of Antoni A and B bodies and overall histopathology, an “encapsulated neurofibroma” seemed best. Rare reports of encapsulated neurofibromas exist, but neurofibromas are generally considered an “unencapsulated” entity. Given the patient was otherwise healthy with an active lifestyle, we conjecture that the capsule observed may have been “reactive,” related to minimal trauma sustained to the area.

Palmoplantar Lichenoid Drug Eruption Secondary to Darbepoetin

Scott Whitecar,* Meagan McGinley Simpson, MD,† and Nicholas Logemann, DO†

*Uniformed Services University of the Health Sciences, Bethesda, MD; and †Department of Dermatology, Walter Reed National Military Medical Center, Bethesda, MD.

We present a unique case of lichenoid drug eruption on the palms and soles of a 62 year-old female with chronic renal failure after introduction of darbepoetin alfa into her medication regimen. Darbepoetin is increasingly being used to treat anemia in patients with chronic renal failure due to its longer half-life, compared to erythropoietin. Lichenoid drug eruptions have a long list of culprit medications. The most common offending medications are angiotensin-converting enzyme (ACE) inhibitors, thiazide diuretics, antimalarials, and gold salts. However, in patients with end-stage renal disease, polypharmacy makes identifying the specific culprit medication a particular diagnostic challenge. Increasing awareness of darbepoetin as a cause of lichenoid drug eruptions can help dermatologists more expediently assess and manage patient symptoms. Additionally, the unique acral distribution should broaden a clinician’s differential when considering drug eruptions.

Factitious Disorder Masquerading as Vasculopathy

Christa Slaught, MD, Olivia M. Lucero, MD, Teri Greiling, MD, PhD, and Kevin White, MD

Department of Dermatology, Oregon Health and Science University, Portland, OR.

Factitious disorder is a mental illness in which individuals act as if they have a physical or cognitive disorder when, in truth, they have caused their symptoms. They are driven by a need to be viewed as ill and may undergo painful or risky interventions to gain attention. We present a case of a 29-year-old woman with recurrent ulcers on the hands, feet and thighs. Extensive evaluation by dermatology, rheumatology, and hematology failed to identify an etiology. Four biopsies collected over 2 years consistently showed full thickness necrosis and intravascular fibrin thrombi with small and medium vessel leukocytoclastic vasculitis. Meanwhile, she suffered repeat hospitalizations and underwent 3 digit amputations for osteomyelitis. Eight years after disease onset, repeat biopsies revealed polarizable foreign material. The patient denied self-harm or alternative treatment modalities, but CT imaging also revealed a foreign body in the soft tissue of the right thigh. This case emphasizes the importance of maintaining suspicion for factitious disorder while shedding light on histopathologic features that may easily be mistaken for true disease.

Strongyloides Hyperinfection Syndrome and Cutaneous Dissemination in a Patient With Sphenoid Wing Meningioma

Worapop Suthiwartnarueput,* Padcha Pongcharoen,† Arisa Kaewkes,‡ and Pochong Rhongbutsri§

*Department of Pathology, Faculty of Medicine, Thammasat University, Thailand; †Dermatology Unit, Department of Internal Medicine, Faculty of Medicine, Thammasat University; ‡Dermatology Resident, Dermatology Unit, Department of Internal Medicine, Faculty of Medicine, Thammasat University; and §Department of Preclinical Science, Faculty of Medicine, Thammasat University.

Background: Strongyloidiasis is a nematode infection caused by Strongyloides stercoralis and is endemic in Southeast Asia. It can result in hyperinfection syndrome and dissemination associated with high morbidity and mortality especially in the immunosuppressed patients caused by corticosteroid.

Case presentation: We present the case of a 47-year-old Thai female who lived in Northeastern Thailand and developed the Strongyloides hyperinfection syndrome and cutaneous dissemination approximately one month after received an oral dexamethasone to reduce an intracranial pressure caused by a large right sphenoid wing meningioma. The diagnosis was confirmed by the identification of numerous Strongyloides larvae from the sputum, stool, and skin biopsies. Despite early diagnosis and treatment, the patient expired on the thirtieth day of admission due to pneumonia with ARDS, candidal septicemia, and septic shock.

Conclusions: Strongyloides hyperinfection syndrome should be suspected in the immunocompromised patients presenting as sepsis, taking the corticosteroid, and live in endemic regions. Microscopic studies from sputum, stool and tissue biopsies should be considered for early diagnosis and treatment.

Key Words: strongyloidiasis, hyperinfection, dissemination, meningioma, steroid

Ischemic Fasciitis in a Young, Physically Active Man

Leah Swanson, Steven Nelson, and David DiCaudo

Mayo Clinic, AZ.

Ischemic fasciitis (IF) is a rare, benign pseudosarcomatous proliferation of atypical fibroblasts. IF is classically described over bony protuberances in immobile elderly or debilitated patients secondary to pressure-induced ischemia. We present a case of IF in a young, active man. A 46-year-old, healthy man presented to clinic. Five months prior, he developed an asymptomatic nodule on the calf. Before onset, he’d begun a daily hiking regimen. After incisional biopsy by outside dermatologist, the lesion mostly regressed. On examination, there was a 1 cm nodule with overlying scar on the right calf. Histopathology showed a spindle cell proliferation within the subcutis. Central fibrinoid necrosis, ganglion-like myofibroblasts, myxoid change, and peripheral fat necrosis were present. Keratin cocktail and smooth muscle actin were negative. Findings were consistent with IF.

Granulomatous Suture Reaction to Monocryl

Sabrina Szabo, DO and Nicholas Logemann, DO

Walter Reed National Military Medical Center, Bethesda, MD.

Monocryl suture is generally thought to be less reactive than other suture materials. A 71 year old male presented to clinic with a 4 mm erythematous scaly papule within a scar. He had a basal cell carcinoma excised from this location 3 and a half months prior to presentation. The area was biopsied to ensure there was no recurrence at this site. The pathology showed a granulomatous dermatitis with multinucleated giant cells phagocytosing a darkly pink to darkly brown amorphous substance, thought to be degrading suture material. No recurrent or residual keratinocytic carcinoma was seen in the biopsy. Papules that form within previous malignancy excision scars should be biopsied to rule out carcinoma, but clinicians should also keep in mind a suture reaction, even if monocryl was used. The histopathologic findings of granulomatous reaction to monocryl, as well as degrading monocryl, are not well described in the literature.

Urticaria Multiforme—A Clinicomorphologic Variant of Urticaria Common in Children

Burak Tekin,* Christine S. Ahn,* Omar P. Sangüeza,* and Lindsay Strowd†

Departments of *Dermatopathology and †Dermatology, Wake Forest School of Medicine, Winston-Salem, NC.

Urticaria multiforme is a clinicomorphologically distinct variant of urticaria first described in 2007, characterized by annular/polycyclic urticarial plaques with central clearing or ecchymotic center, usually associated with acral edema. We describe a 22-month-old female with Denys-Drash syndrome and Wilms tumor who presented to the dermatology clinic for an intermittent and recurrent rash on the body. On examination the patient had urticarial plaques on bilateral arms with an atypical targetoid appearance. No mucosal involvement was noted. Biopsy demonstrated dermal edema with a diffuse perivascular and interstitial infiltrate with neutrophils and lymphocytes. Based on the lesional morphology and absence of features of vasculitis, the patient was diagnosed with urticaria multiforme. Despite its dramatic clinical appearance, urticaria multiforme is a benign, reactive process that may occur following medication use or antecedent infection. Although diagnosis is often based on clinical findings, clinicians and dermatopathologists should be aware of urticaria multiforme, as histopathology can help exclude entities with similar clinical features such as erythema multiforme, acute hemorrhagic edema of infancy, or serum sickness-like reaction.

Early Disseminated Lyme Borreliosis (Erythemata Migrantia): A Diagnostic Challenge

Mariantonieta Tirado, MD* and Almut Böer-Auer, MD†,‡

*Pathology Department, Baylor Scott & White Health Center, Temple, TX; †Department of Dermatology, Münster University; and ‡Dermatologikum, Hamburg, Germany.

Multiple erythemata migrantia are a rare manifestation of disseminated early-stage borrelia infection. Clinically, erythemata migrantia present as multiple ring shaped or homogenous livid maculae and plaques persisting over days or weeks. Children frequently present with symmetrical erythema on the face. Extracutaneous symptoms include fatigue, malaise, arthralgias, myalgias, headache, meningeal signs, subclinical hepatitis, lymphadenopathy, fever, chills, vertigo, nausea and anorexia. Some patients do not remember a tick bite. Histopathologically, erythemata migrantia are non-specific but specimens often show superficial and deep perivascular infiltrates composed mainly of lymphocytes. Plasma cells are an inconsistent finding. Sometimes interstitial infiltrates containing macrophages are observed. Oral doxycycline or parenterally administered ceftriaxone are effective treatments but should be given for 3 weeks. We discuss the differential diagnosis and examples of this unusual form of disseminated early-stage borreliosis which may be unrecognized and should be included in the differential diagnosis of multiple annular dermatoses including persistent urticarial, multiple granulomata annulare, erythema annulare centrifugum, multilocular fixed drug eruption and parvovirus B19 infection among other.

A Case of Accessory Scrotum

Mariantonieta Tirado, MD,* Martin P. Fernandez, MD,* and Almut Böer-Auer, MD†,‡

*Pathology Department, Baylor Scott & White Health Center, Temple, TX; †Department of Dermatology, Münster University; and ‡Dermatologikum, Hamburg, Germany.

Accessory scrotum is considered a rare congenital abnormality and has been observed in isolation or in conjunction with other anorectal/urogenital abnormalities. We report on a 16-month-old boy who presented with an asymptomatic lesion localized over the midline scrotum. It had continued to grow largely in proportion to the patient's growth and had become more raised and mobile. The lesion was a 2 × 1.5 × 0.8 cm soft, mobile, pink to flesh colored lesion, with several components and redundant skin. There were no urogenital nor anorectal abnormalities. The toddler underwent a simple surgical excision of the scrotal lesion. Histologic examination revealed a papillary epidermis, dermal rudimentary dartos fibers and scattered vessels with mild perivascular lymphohistiocytic infiltrates. Accessory scrotum is a congenital abnormality that can be rarely encountered as a dermatopathological specimen. It is a hamartoma that recapitulates the normal tissue at the same site. Its accurate diagnosis is important in order to investigate a possible association with other anorectal and or urogenital abnormalities.

Folliculotropic Mycosis Fungoides With Keratosis Pilaris-Like Histopathologic Features: A Challenging Diagnosis

B. Joel Tjarks, MD and Jaqueline M. Junkins-Hopkins, MD

Geisinger Medical Center, Danville, PA.

Background: Folliculotropic mycosis fungoides (FMF) presents with alopecic patches/plaques and often has a poor prognosis. Rarely, keratosis pilaris (KP)-like clinical and histologic features are present. This subtype tends to be indolent, but the diagnosis may be missed. We present a case of FMF with KP-like histopathologic features.

Case: A 70-year-old male presented to the dermatology clinic with 4 years of dusky red/brown follicular macules and follicular papules on the extremities and dry/wrinkled patches on his trunk/buttock. Biopsies were initially interpreted as non-specific perivascular inflammation, due to negative T-cell receptor clonality studies. Additional clinical-pathologic review revealed a mild folliculotropic and epidermotropic infiltrate of atypical lymphocytes and follicular plugging. The epitheliotropic lymphocytes were CD3+/CD4+/CD5+/CD7 dim/CD8(−). Clinical correlation confirmed FMF.

Conclusions: This KP-like histologic subtype of FMF has a better prognosis than advanced-stage FMF, but the diagnosis can be challenging, requiring clinical-pathologic-correlation. This case adds to the dearth of information currently available regarding an unusual presentation of this uncommon entity.

Cutaneous Angiosarcoma: A Case Demonstrating the Utility of Mapping Biopsies

David Ullman, MD, Mariam Youssef, MD, Danielle Fasciano, DO, and Peter Pavlidakey, MD

University of Alabama at Birmingham, Department of Pathology, Birmingham, AL.

An 82-year-old female with angiosarcoma of the scalp presented from an outside hospital for treatment. A previous biopsy revealed a dermal angiosarcoma with 2 mitoses per 10 HPFs, necrosis, and HHV-8 negativity. The patient had initially noted a scalp lesion 3 weeks previously. At that time, the patient was asymptomatic. She reported a previous history of scalp basal cell carcinoma 3 years prior, treated with resection but no radiation. Now she presents with an approximately 2 cm circular lesion on the center of her scalp. After the patient’s head was shaved, the entire scalp was revealed to be erythematous with no discrete masses. Multiple punch biopsies were utilized to examine the extent of disease and guide therapy. Unfortunately, the malignancy extended across the entire scalp. The diffuse involvement of the scalp rendered the patient a non-surgical candidate. This case highlights the clinically difficult nature of cutaneous angiosarcoma and the utility of mapping biopsies to delineate the extent of disease.

Proliferating Pilar Tumor Imitating Carcinoma

David Ullman, MD, David Dorn, MD, Carlos Prieto-Granada, MD, and Peter Pavlidakey, MD

University of Alabama at Birmingham, Department of Pathology, Birmingham, AL.

A 64-year-old male presented with multiple scalp masses ranging from 2.3 to 6.3 cm in greatest dimension, the largest of which had doubled in dimension over the past year prompting the patient to seek treatment. Interestingly, the patient's grandmother had similar scalp masses and his 3 siblings previously had “knots” on their back removed. Unfortunately, the diagnoses for these lesions were not available. The patient’s scalp lesions were excised with clear margins. Gross examination of the largest lesion revealed a polypid, exophytic, well-circumscribed mass with a bosselated pushing border. Microscopic examination revealed a proliferating pilar tumor with multifocal atypia, hyalinization and dystrophic calcification with no definitive invasive component. While the atypia and size of the lesion are worrisome, the gross appearance and lack of an invasive component favored the diagnosis of proliferating pilar tumor with possible low-grade aggressive clinical behavior. The smaller lesions were diagnosed as pilar cysts. This case highlights the importance of a thorough gross examination in diagnosing proliferating pilar tumors. Family history is also useful in suggesting the possibility of hereditary familial pilar cyst syndrome.

Improved Turnaround Times for External Dermatopathology Consultations With Up-Front Ancillary Testing by the Consulting Pathologist

J. Vuong and K. Naert

Department of Pathology and Laboratory Medicine, University of Calgary.

This study evaluated the case types received for external dermatopathology consultation at Calgary Laboratory Services (CLS), a centralized laboratory in western Canada with around 1000 dermatopathology consults annually. We assessed whether turnaround times could be improved if the consulting pathologist performed up-front ancillary testing prior to referral, and what types of tests were most useful. We compared the turnaround times for dermatopathology consults with or without prior ancillary testing for 13 months. The consultant turnaround times were significantly shorter when the ancillary testing was ordered prior to consultation for both melanocytic and inflammatory lesions but not for all other pathologies. Dermatopathologists tended to order MelanA or MelanA with Ki-67 for melanocytic lesions and special stains to rule out infectious organisms and colloidal iron for mucin for inflammatory lesions. In conclusion, consultant turnaround times were improved when requesting pathologists ordered ancillary testing for melanocytic and inflammatory lesions but not for other case types. Awareness of this may help referring pathologists manage cases and improve turnaround time.

An Unusual Case of Merkel Cell Carcinoma With Low Tumor Mutational Burden on Non-Sun-Exposed Skin of an African American Female

Timothy R. Wysozan,* Matthew B. Strausburg,† Ahmad Al-Hader,* Matthew Kuhar,* and Ahmed K. Alomari*

*Indiana University School of Medicine, Indianapolis, IN; and †Turkle & Associates Plastic Surgery and Dermatology, Indianapolis, IN.

We report a case of a 69-year-old African American female with a history of prolonged corticosteroid use who presented with a several-week history of painful subcutaneous nodule on her right lateral thigh. An excisional biopsy revealed a dyshesive small round blue cell tumor with nuclear molding and positive staining for CK20 (dot-like), synaptophysin, and Merkel-cell polyomavirus, consistent with Merkel cell carcinoma. The patient underwent complete excision and right groin sentinel lymph node biopsy, which was extensively involved with perinodal lymphatic invasion. Next generation sequencing of the primary lesion revealed a stable microsatellite status, low tumor mutational burden, and several variants of unknown significance. The patient was further managed with adjuvant radiation therapy to the right groin. The authors present this case as an unusual manifestation of Merkel cell carcinoma occurring on non-sun-exposed skin of a chronically immunosuppressed African American female and to provide insight on the genetic makeup of such lesions.

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