Multinucleate cell angiohistiocytoma. A review and report of four cases.

Multinucleate cell angiohistiocytoma (MCA) was first characterized by Smith & Wilson-Jones. Although only a few cases have been published, this very characteristic benign tumor is probably not rare. The clinical pictures are firm circumscribed papules, mainly of the hands, which progress slowly over the years. The histologic features show an increase of capillaries and venules in the reticular dermis, overlaid by epidermal hyperplasia. Bizarre-shaped multinucleate cells are present between the vessels, and factor XIIIa-positive interstitial cells are increased in number. MCA can be easily recognised if the pathologist is aware of the diagnosis. We present here the clinical, histologic and immunopathologic features of 4 new cases and review the literature.