Reactive angioendotheliomatosis in association with a well-differentiated angiosarcoma.

A 55-year-old white female with a complex medical history including mixed connective tissue disease and peripheral vascular disease developed a group of red-purple papules on her proximal medial thigh that was followed, five months later, by the development of a large violaceous patch. She reported a history of radiation to this site (for melanoma) during her childhood. She was admitted to the hospital with a presumptive diagnosis of cellulitis, but failed to respond to antibiotics. A biopsy was performed and demonstrated a well-differentiated angiosarcoma arising in conjunction with reactive angioendotheliomatosis. Excision of the lesion was performed, and fifteen months of follow-up have shown no recurrence or metastasis.