Composite tumor consisting of dermatofibrosarcoma protuberans and giant cell fibroblastoma associated with intratumoral endometriosis. Report of a case

We present a unique case of composite skin tumor of the vulva consisting of dermatofibrosarcoma protuberans (DFSP) and giant cell fibroblastoma (GCF) with an intratumoral focus of endometriosis. A 31-year-old female with a 10-year-history of a recurring subcutaneous tum or in the vulvar area underwent excision of the seventh recurrence of the t umor. Microscopic examination revealed a composite fibro-histiocytic tumor consisting of DFSP and GCE Additionally, a focus of endometriosis within th e tumor tissue was found. Malignant transformation of extragonadal endometriosis has already been des cribed; we present, however, the occurrence of a focus of endometriosis wit hin the tissue of a hormonally independent soft tissue rumor. There is a po ssible link to the occurrence of cutaneous endometriosis at previous surger y sites and in the scars. The presence of endometriosis within the soft tis sue tumor represents, to the best of our knowledge, a previously undescribe d collision phenomenon.