Atrophic dermatofibroma and dermatofibrosarcoma protuberans.

Dermatofibroma and dermatofibrosarcoma protuberans usually are seen as firm nodules in the skin. We have observed several patients, all female, with an atrophic or depressed lesion on the chest or back. When biopsy was done, the biopsy punch was often noted to sink into the lesion. In each case the biopsy specimen showed a cellular dermatofibroma or dermatofibrosarcoma protuberans. The correct diagnosis was rarely suspected clinically. This uncommon clinical presentation may be related to the marked cellularity of the fibrous tumors in this series.