A Clinicopathologic Study of Merkel Cell Carcinoma / 대한피부과학회지

ABSTRACT

BACKGROUND: Merkel cell carcinoma is a rare neuroendocrine tumor that typically presents as indurated nodules in elderly patients. It has an aggressive behavior and thus, such incidence has been increasing. OBJECTIVE: Our purpose was to analyze clinical and histological characteristics of Merkel cell carcinoma, and to obtain a better understanding of this rare malignancy. METHODS: We conducted a clinicopathologic evaluation of 11 patients from our center during 21 year period (1989~2010). We investigated personal and clinical information, including age, sex, time of onset, past history, histologic findings and clinical manifestations. RESULTS: The age of the 11 patients ranged from 48 to 84, and the mean age of onset was 62.3, with a slight female predominance (11.7). The most prevalent site was the face then followed by the extremities. Subcutaneous nodular lesion with overlying erythema was the most common finding (72.7%, 8/11). Protruding tumorous lesions were 18.2% (2/11) and palpable lymphadenopathy was 9.1% (1/11), respectively. Histopathologically, pleomorphic atypical cells and granular nuclear dots ("salt and pepper") were observed. Immunohistochemical study showed positivity for pan-cytokeratin (CK), cytokeratin (CK20), CD56, synaptophysin, chromogranin (90%, 81.8%, 100%, 85.7%, 83.3%) and negative result for leukocyte common antigen (LCA, 0/7), and thyroid transcription factor-1 (TTF-1, 0/4), S100 (0/4). CONCLUSION: Merkel cell carcinomas were more frequent in old females and were rare in immunocompromised patients in Korea. Histologic and immunohistochemical features were similar to previous studies, but there was a case of rare type (CK7+/CK20-) of Merkel cell carcinoma. Surgery is a treatment of choice in Merkel cell carcinoma. But radiation or chemotherapy can be used as an adjuvant therapy. Based on this study, characteristics of Merkel cell carcinoma in Korea can be elucidated with more future cases.