A Case of Pigmented Dermatofibrosarcoma Protuberans ( Bednar Tumor ) Showing Atrophic Lesions

Lee, Jong Ho; Jung, Doo Yeoul; Lee, Sook Kyung; Lee, Won Woo

Abstract

A Bednar tumor is a variant of dermatofibrosarcoma protuberans(DFSP). The clinical and histopathological findings of Bednar tumors are identical to DFSP except for the presence of melanin-containing cells scattered within the lesion, so called pigmented DFSP. The majority of Bednar tumors are seen as DFSP present as multinodular protuberant masses in the skin. They can also present as an atrophic depressed scar-like lesions without any nodularity. We report an uncommon clinical presented case of a Bednar tumor on the back in a 22-year-old female. She presented with an asymptomatic, firm, bluish, chestnut sized, depressed and atrophic lesion on the back which had been present for 6 years. A Histopathological examination revealed massive proliferation of spindle-shaped cells arranged in a tight storiform pattern mixed with scattered pigmented cells. On immunohistochemical staining, the tumor cells were positive for vimentin, a -l-antitrypsin, and CD34, but were negative for cytokeratin, neurofilament, and factor XIIIa. The majority of the tumor cells was negative and the pigment cells were positive for the S-100 protein. The patient was treated by a wide local excision of the lesion. There has been no evidence of recurrence after 20 months post-operative follow up.