Dermatofibrosarcoma protuberans occurring in a smallpox vaccination scar.

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive, rarely metastatic, spindle cell tumor. Trauma has been associated with its development. Since the 1940s, malignant tumors have been described to occur in sites of smallpox vaccination scars. Five cases in the literature document DFSP arising in sites of prior immunizations. We report a case of DFSP occurring in a smallpox vaccination scar and review the available literature.