Epithelioid vascular tumors of bone: a review and proposal of a classification scheme.

Skeletal vascular tumors composed of epithelioid endothelial cells commonly result in diagnostic difficulty. Although tumors with this morphology have been recognized for many years, there is a considerable degree of confusion regarding their nomenclature and classification. In this article what is believed to represent the morphologic features of this family of tumors is outlined, the historical context of epithelioid endothelial tumors is briefly discussed, and pertinent literature and texts pertaining to the subject is reviewed. It is proposed that the osseous epithelioid endothelial tumors should be classified in a similar manner to their soft tissue counterparts and it is suggested that this approach should help to clarify the confusion surrounding this subject of surgical pathology.