Dermatofibrosarcoma protuberans (DFSP) is a fibrohistiocytic tumor, which grows slowly and tends to relapse locally after inadequate removal. DFSP is frequently difficult to distinguish from other fibrohistiocytic tumors; however, anti-CD34 staining is useful for differential diagnosis.
We reported a 67-year-old male with a DFSP on his right cheek. He had noticed a subcutaneous tumor on the right side of his mouth for 20 years. The tumor had formely grown slowly, but it grew rapidly in 1999. We then performed wide excision including facial muscles and skin grafting. Histopathologicaly the tumor was composed of uniform spindle-shaped and mild atypical fibroblast-like cells. Most parts of the tumor formed a storiform pattern. Spindle-shaped cells were showed positive with anti-CD34 staining. We diagnosed this case as a giant DFSP on the cheek. [Skin Cancer (Japan) 2001; 16: 324-327]