Epithelioid hemangioendothelioma (histiocytoid hemangioma) of the palate.

The first case of epithelioid hemangioendothelioma involving the oropharynx is described. A 25-year-old woman developed a mass on the palate which noted to enlarge during the first trimester of pregnancy. Biopsy revealed a cellular tumor initially considered to be of epithelial origin. Vascular differentiation of the tumor was confirmed, however, by positive lectin histochemistry for Ulex europaeus, by evidence of immunoreactivity for factor VIII-related antigen, and by ultrastructural identification of endothelial features. The patient remains free of tumor 21 months after complete excision. Because of the potential for misdiagnosis, epithelioid hemangioendothelioma should be considered in the differential diagnosis of oropharyngeal malignancies. The effect of pregnancy on the development and growth of vascular tumors such as epithelioid hemangioendothelioma remains uncertain.