Merkel細胞癌

抄録

A 77-year-old woman had noticed a red papule on her head about 2 years before. The eruption gradually increased in size. So she visited our clinic on June 19th, 1995. Clinically, it consisted of the firm, nodular, reddish lesion, the size of which was 25×20mm in diameter. Total resection was carried out 1cm apart from the margin of the lesion. Histologically, tumor cells showed a trabecular pattern or bands with a rather uniform appearance, which extended from the dermis into subcutis. The tumor cells had oval, vesicular nuclei and scanty cytoplasm. Numerous mitotic figures were also present. Ultrastructurally, there were observed paranuclear aggregation of intermediate filaments and dense core neurosecretory granules which were located in the cytolasmic processes or near the Golgi apparatus. Immunohistochemically, cytokeratin 8, 18, 19, 20 and epithelial membrane antigen were positively stained within tumor cells. Tumor cells showed partially positive labeling against chromogranin A, neurofilament and neuron specific elorase. S-100 and HMB-45 were negative. From the findings above, this case was diagnosed as Merkel cell carcinoma. It was suggested that perinuclear bandles were related to the partial positive staining of neurofilament.