Multinucleate cell angiohistiocytoma: a distinct entity diagnosable by clinical and histologic features.

BACKGROUND: Multinucleate cell angiohistiocytoma is a newly described entity; examples from the United States have not yet been reported.

OBJECTIVE: Our purpose was to analyze the clinical and histologic features of this entity and confirm or refute its existence.

METHODS: Seven cases were analyzed clinically and by light microscopy.

RESULTS: Multinucleate cell angiohistiocytoma typically occurs in middle-aged women and consists of multiple, grouped, red-brown to violaceous papules that are dome-shaped or flat-topped, roundish and smooth in outline, sharply circumscribed, and occasionally coalescent. Typical sites are the legs, thighs, and backs of hands and fingers. Microscopic features are an increased number of blood vessels (usually capillaries and venules) that are small, rounded, and not well grouped, together with multinucleated histiocyte-like cells with scalloped borders.

CONCLUSION: Multinucleate cell angiohistiocytoma is a distinct entity that is diagnosable clinically and histopathologically.