Multinucleate cell angiohistiocytoma: a case report and review of the literature.

Multinucleate cell angiohistiocytoma (MCAH) is a rare, benign vascular proliferation. Fewer than 80 cases have been reported to date, which may relate to under-recognition of this entity. Lesions are commonly asymptomatic and appear as erythematous to violaceous papules on the lower extremities and dorsal hands of middle-aged to elderly women. The characteristic histopathologic and immunohistochemical features of MCAH are essential for definitive diagnosis of MCAH. Multinucleate cell angiohistiocytoma follows a slowly progressive course, although spontaneous regression has been reported in rare cases. We present a case of MCAH to increase awareness and elucidate the characteristic clinical and histopathologic features of this disorder.