Epithelioid hemangioendothelioma with osteoclastlike giant cells.

This article describes histopathologic and immunohistologic features of an epithelioid hemangioendothelioma that presented in the neck of a 40-year-old man. This tumor was unusual because of the presence of osteoclastlike giant cells scattered throughout the entire lesion. The tumor cells reacted positively for factor VIII-related antigen, and the osteoclastlike giant cells were reactive for KP1 antibody, a macrophage-associated antigen. We are aware of only one other previously reported example of soft-tissue epithelioid hemangioendothelioma with an abundance of osteoclast-like giant cells.