SECTION II: ORIGINAL ARTICLES
Tricholemmal carcinoma, a rare neoplasm, was first described by Holmes7 in 1968 as tricholeptocarcinoma. It is similar to the benign form, a tumor of the external hair sheath. Tricholemmal carcinoma is found in elderly individuals on sun-exposed skin, involving the head and neck, upper and lower eyelids, ears, trunk, and upper and lower extremities. According to Schell and Haneke,11 in their study it occurred in 0.05% of the patients who had histopathologic examinations. Consequently, it is 2.5 times more rare than the benign form. Because no characteristic clinical signs of tricholemmal carcinoma exist, the diagnosis may be made based on the histologic resemblance of the tumor to the outer root sheath and after exclusion of other types of clear-cell neoplasms such as sebaceous carcinoma, mucin-producing adenocarcinoma, metastatic renal cell carcinoma, balloon cell malignant melanoma, and most sweat gland carcinomas.
Investigations of tricholemmal carcinoma are rare, and authors report on an average of seven to 13 cases each (Boscaino et al2 [seven cases], Grouls5 [two cases], Swanson et al12 [10 cases], Wong and Suster14 [13 cases], and Schell and Haneke11 [11 cases]). Although the malignancy is high, most of the tumors behaved similar to the benign ones, and aggressive behavior was found in only one patient with distant metastases.1 Therefore, it seems wise to treat this tumor by conservative but thorough excision, and to do regular clinical examinations to detect possible recurrences.
A 64-year-old man had a 6- x 6-cm cutaneous tumor at the lateral aspect of the right knee at the height of the fibular head. The tumor was resected because it developed a central ulceration. Histologic diagnosis showed a megatrichoepithelioma with formations of squamous cells with clear cytoplasm including hair-like particles, surrounded by fibromyxoid stroma. Areas of nuclear polymorphism and mitoses were remarkable. Two years later, a local recurrence with inguinal lymph node metastases was found and resected. The histologic diagnosis was changed to tricholemmal carcinoma with lymph node metastases. Now the basaloid epithelial cells showed a strong mitotic activity including atypical mitoses and an infiltrative and destructive tumor growth was obvious. Immunocytochemistry revealed high molecular weight expression (HMW) and epithelial membrane antigen (EMA). Carcinoembryonal antigen (CEA) was negative in the tumor cells and only positive in the sweat glands. No reaction of Vimentin and S100 came to view in the tumor cells. The differential diagnosis includes clear-cell squamous carcinoma, cystic, keratinizing or adenoid basal cell epithelioma, anaplastic carcinoma, or even epitheloid hemangioepithelioma or malignant melanoma. All these tumors, however, show a different histologic pattern, local tumor growth, and a different immunohistochemistry.10
The resection of the tumor was incomplete. Three recurrent resections have been done. During resection of the inguinal lymph nodes, local infiltration of the tumor into the femoral artery and vein was found. A Goretex™ stent (WL Gore & Associates Inc, Flagstaff, AZ) was implanted for revascularization of the vessels. Three months after the last surgery, a local recurrence in the distal right thigh and a tumor conglomerate in the small pelvis were found; radiation with 5 Gy was administered without eradication of the tumor.
New pain in the left lower leg led to a radiographic examination and the diagnosis of osteolytic metastasis in the middle of the tibial shaft. Radiation with 5 Gy was administered.
The physical examination showed a massive 6- x 6-cm pretibial swelling of the left lower limb without reddening or induration, with pressing and knocking pain, and a lack of extension of the right knee of 5°. The flexion attained was 95°.
The radiographic examinations of the left lower leg revealed a metastasis in the middle of the shaft of the tibia. The finding was followed by radiation. Eight months later, there was extended osteolysis of 8 cm with a pathologic fracture without dislocation. A small osteolysis of the fibula at the middle to the distal thirds also was found (Fig 1). A T1-weighted MRI scan showed considerable extraosseous extension of the tibial metastasis with 9- x 5-cm tumoral destruction of the tibia. The fibula had an approximately 3-cm diameter lesion in the middle of the diaphysis with a strong, central decreased contrast uptake and an approximately 2-cm wide circular extraosseous tumor into the deep compartments (Fig 2). A CT scan of the thorax with contrast material did not show mediastinal or hilary tumoral findings or metastases.
A magnetic resonance tomogram of the pelvis and the right upper thigh showed lymph nodes that were suspected of being metastatic close to the iliac vessels with compression of the internal iliac vein. Multiple tumoral nodules in the midside proximal part of the thigh with paraosseous extension were seen.
A CT scan of the abdomen with contrast material showed no liver metastases. In the proximal right medial thigh, lymph nodes suspected of being metastatic were seen. A thrombosis of the right external iliac vein and closing of the right external iliac artery were suspected.
Two-phase bone scintigraphy with technetium [99 mTc] 3,3-diphosphono- 1,2 propane dicarboxylic acid showed heightened mineral uptake in the tumor of the lower leg in the blood pool phase and the bone scan images. The findings were interpreted as a hyperactive border of a central necrotic metastasis.
The laboratory values all were normal except for a slight increase of the serum glucose. Because of evidence of a recurrence of the tumor in the right proximal thigh and pelvis and extracompartmental tumor infiltration of the tibial metastasis with infiltration of the deep compartments of the lower leg, radical surgery was not possible. A marginal tumor resection was done with osteosynthesis with bone cement and an 18-hole limited contact dynamic compression plate (Synthes Corporation, Oberdorf, Switzerland) (Fig 3). The postoperative course was uneventful.
The pathologic and anatomic examinations of the specimen showed macroscopic fragile bone tissue of the left tibial shaft. Histologically, the bone marrow space was filled with malignant epithelial tumor tissue, with identical characteristics to the primary tumor (Fig 4). In the bone marrow, there was a fibrotic stroma with large lobules filled with polymorphic epithelial cells. Only traces of trabecular bone were seen (Fig 5). The metastatic tumor tissue in the lymph nodes and in the bone lesion showed the same histologic pattern as the primary skin tumor. In addition, immunohistochemical reactions (HMW, EMA, CEA, Vimentin, S100) of all three tissues were identical. Because the tumor showed no positive reaction on S100 and HMB45, the specific melanoma marker, bone metastasis of malignant melanoma could be excluded. Consequently, metastasis of tricholemmal carcinoma was diagnosed the first time. Radiographic control films obtained 10 weeks after surgery revealed tumor progression with extension of the osteolytic process in the fibular head and in the area of the osteosynthesis. Because of the pretreatment, radiotherapy was not possible, therefore, chemotherapy was administered. The 1-year followup showed identical clinical findings. Radiologic control films revealed only slight progression. The patient currently requires crutches.
The current case of a tricholemmal carcinoma is different from former reported cases. When surgery was done for the first time, the tumor was 6 cm in diameter with a central ulceration. Such a large primary tumor was described only once by Cribier et al.3 The multiple local recurrences at the right knee and metastases in the inguinal lymph nodes are uncommon, and the tibial metastasis of the contralateral tibia with excessive extraosseous tumor spreading into the entire lower leg has not been reported previously. The first assumption that the tumor in the right leg might be a second tumor was disregarded after reexamination of all histologic slices from 1996 until 2001. Identical histologic features with the primary tumor were discovered. It is not known whether the course of metastasis was hematogenic or lymphogenic. A lymphogenic course in the metastases located on the right side can be supported because metastases were found in the inguinal and paraaortal lymph nodes. Although tumor cell nests were found in bigger lymphatic spaces in the left-sided tibial metastasis, lymphogenic metastasis would be a rare diagnosis. Metastasis of the tumor to the left leg more likely had a hematogenic course.
The tumor in the current patient was undoubtedly a tricholemmal carcinoma. Progression of the tumor metastases contradicts that in existing publications. With the exception of Amaral et al,1 other authors described a benign clinical progress of tricholemmal carcinoma.2–14
This tumor should be treated with conservative but thorough excision. Regular clinical examinations should be done to detect possible recurrences but there is no guarantee of lack of recurrences.
1. Amaral ALMP, Nascimento AG, Goeller JR: Proliferating pilar (tricholemmal) cyst: Report of two cases, one with carcinomatous transformation and one with distant metastases. Arch Pathol Lab Med 108:808–810, 1984.
2. Boscaino A, Terracciano LM, Donofrio V, Ferrara G, De Rosa G: Tricholemmal carcinoma: A study of seven cases. J Cutan Pathol 19:1994–1999, 1992.
3. Cribier B, Lipsker D, Grosshans E: Eccrine porocarcinoma, tricholemmal carcinoma and multiple squamous cell carcinomas in a single patient. Eur J Dermatol 9:483–486, 1999.
4. Dailey JR, Helm KF, Goldberg SH: Tricholemmal carcinoma of the eyelid. Am J Ophthalmol 115:118–119, 1993.
5. Grouls V: Tricholemmale Keratose und tricholemmales Karzinom. Hautarzt 38:335–341, 1987.
6. Headington JT: Tricholemmal carcinoma. J Cutan Pathol 19:83–84, 1992.
7. Holmes EJ: Tumors of lower hair sheath: Common histogenesis of certain so-called “sebaceous cysts,” acanthomas and “sebaceous carcinomas. Cancer 21:234–248, 1968.
8. Krumrey KW: Das tricholemmale Karzinom: Ein Fallbericht mit Literaturübersicht. Aktuelle Derm 10:70–72, 1984.
9. Lee JY, Tang CK, Leung YS: Clear cell carcinoma of the skin: A tricholemmal carcinoma? J Cutan Pathol 16:31–39, 1989.
10. McKee PH: Tumors of the Epidermal Appendages. Pathology of the Skin. Ed 2. Philadelphia, JB Lippincott 15.1–15.87, 1989.
11. Schell H, Haneke E: Tricholemmales Karzinom: Bericht über 11 Fälle. Hautarzt 37:384–387, 1986.
12. Swanson PE, Marrogi AJ, Williams DJ, Cherwitz DL, Wick MR: Tricholemmal carcinoma: Clinicopathologic study of 10 cases. J Cutan Pathol 19:100–109, 1992.
13. Ten Seldam REJ: Tricholemmocarcinoma. Australas J Dermatol 18:62–72, 1977.
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14. Wong TY, Suster S: Tricholemmal carcinoma: A clinicopathologic study of 13 cases. Am J Dermatopathol 16:463–473, 1994.