Histiocytoid hemangioma of the skin and scapula. A case report with electron microscopy and immunohistochemistry.

This report presents the interesting case of a 50-year-old white man with an unusual benign tumor composed predominantly of a proliferation of atypical endothelial cells combined with a variable inflammatory response. This case represents an instance of the recently renamed entity "histiocytoid hemangioma" in which two organ systems are involved. Both skin and bone showed typical lesions. No physical connection jointed the separate lesions. The results of examination by light microscopy, electron microscopy, and immunoperoxidase examination for lysozyme and Factor VIII are reported. The significance of this case is that it supports the concept of classifying similar vascular lesions, despite varied organ system origin, into a single entity, the histiocytoid hemangioma.