Malignant histiocytosis presenting with vasculitis and cutaneous erythrophagocytosis.

We report a case of malignant histiocytosis that presented initially as a cutaneous vasculitis without malignant features. A subsequent biopsy specimen of an erythematous skin lesion showed erythrophagocytosis by normal-appearing histiocytes within the subcutis. The recognition of erythrophagocytosis was followed by systemic symptoms and signs of malignant histiocytosis and a rapidly deteriorating clinical course. Possible mechanisms for erythrophagocytosis are discussed, and other diseases associated with this histologic finding are reviewed briefly.