Multinucleate cell angiohistiocytoma: an acquired vascular anomaly to be distinguished from Kaposi's sarcoma.

Multinucleate cell angiohistocytoma is a newly described benign vascular condition that usually arises on the extremities of women over the age of 40 as discrete grouped violaceous erythematous papules, often mimicking Kaposi's sarcoma. Of 10 patients, nine were women aged between 37-66 (average 51.5) years at the onset of their condition. The legs, and in particular the calves and thighs, were the commonest sites to be involved. However, in three patients the papules were confined to the back of the hands, and the male patient had lesions across the front of the chest. Bilateral lesions occurred in four patients. Histologically, the salient features were proliferation of capillaries and small venules at the level of the subpapillary plexus and the mid dermis, in association with prominent connective tissue cells and larger angulated multinucleate cells. Detailed histochemical and immunocytochemical studies have not elucidated the histogenesis of the multinucleate cells that seem to be a characteristic feature of this condition.