Abstract
A 46-year-old woman visited our clinic with a history of a tumor on her left great toe. The tumor was excised twice by a local physician. No histological examination was performed for the first tumor. The recurrent tumor was diagnosed as spindle cell type squamous cell carcinoma with residual tumor cells at the surgical margin. Histologically, the tumor was composed of round or polygonal cells with clear cytoplasm and vesicular nuclei. Immunohistochemically, the tumor was positive for vimentin and NSE, partly positive for S-100, cytokeratin, but negative for HMB-45, MART-1 and Leu-7. Left inguinal lymph node swellings were excised. Histological features were the same as the tumor of the toe and it was immunohistochemically positive for S-100, HMB-45, MART-1 and CEA, partly positive for vimentin, and negative for cytokeratin and Leu-7. In transmission electron microscopy, free immature melanosomes were found in the tumor cells. Although it is difficult to distinguish between clear cell sarcoma, fibrosarcoma and spindle cell-shaped squamous cell carcinoma, we successfully diagnosed this tumor as clear cell sarcoma by electron microscopic studies. [Skin Cancer (Japan) 2006; 21: 158-163]
