A CASE OF BEDNAR TUMOR - IMMUNOHISTOCHEMICAL POSITIVITY FOR CD34

A 42-year-old Japanese man with a Bednar tumor is described. The skin showed a slightly elevated, red, partially dark blue, dermal nodule gr owing into the deep subcutaneous tissue. The histological specimen sho wed two types of tumor cells, spindle-formed cells with no melanin gra nules and melanin-laden cells. Immunohistochemical stainings for CD34 and S-100 protein revealed that the former cells showed positivity onl y for CD34, while the latter were only pos itive for S-100 protein. Th ese results suggest that the Bednar tumor is a dermatofibrosarcoma pro tuberans in which melanin-laden cells coexist.