Metastatic dermatofibrosarcoma protuberans mimicking meningioma.

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive fibrohistiocytic tumor of intermediate malignancy with potential for local recurrences and with a small, but well recognized risk of distant metastases. We report a case of a 43-year-old Filipino male with an otherwise typical cutaneous DFSP followed 4 years later by a local recurrence of tumor with subsequent pulmonary metastasis at year 5, and 3 sequential central nervous system (CNS) metastases at years 5, 6, and 12 following the original diagnosis of DFSP. Recurrent and metastatic tumors showed areas of fibrosarcomatous change, high cellularity, high mitotic rate (10 - 15 per 10 high power fields), loss of CD34 expression, and aneuploidy. DFSP has not been previously reported to metastasize to the CNS. In addition, we report complex karyotypic aberrations within the metastasis, which have not been previously associated with DFSP. The dural-based location of the intracranial metastasis, together with the light- and electron-microscopic appearance, could cause diagnostic confusion with an anaplastic syncytial meningioma.