Multinucleate cell angiohistiocytoma

We report a case of multinucleate cell angiohistiocytoma occurring in a 50-year-old woman and presenting with a 4-year history of asymptomatic red papules on the face. Histologically, there was a dermal vascular proliferation associated with numerous multinucleate cells. Immunohistochemical studies showed vascular spaces surrounded with mature vascular endothelial cells, and the presence of numerous interstitial factor XIIIa⁺ cells. Multinucleate cells exhibited intermediate filaments of the vimentin type, but were not stained by endothelial cell or macrophage markers, and were factor XIIIa^-. This condition must be addressed in the differential diagnosis of other skin vascular proliferations, such as Kaposi's sarcoma and angiofibromas.