Primary intraoral epithelioid hemangioendothelioma presenting in childhood: review of the literature and case report.

Epithelioid hemangioendothelioma (EH) is a recently described vascular neoplasm of borderline or intermediate malignant potential. This tumor arises from medium- to large-sized vessels, primarily involves the soft tissues of the extremities as well as the liver and lung, and rarely occurs in the head and neck region. Only eight well-documented cases of intraoral EH have been reported. We present an additional pediatric case of EH confined to the oral cavity and review the literature regarding EH presenting as an intraoral mass. EH is characterized histopathologically as an epithelioid lesion arranged in nests, strands, and trabecular patterns with infrequent vascular spaces. Occasional erythrocytes within intracytoplasmic lumina may be seen in tumor cells. Ultrastructural examination typically shows intracytoplasmic lumina with pseudopodial cellular membrane extensions. The cytoplasm usually contains intermediate filaments infrequently associated with Weibel-Palade bodies. Neoplastic cells are immunoreactive for factor VIIIR:Ag and Ulex europaeus. Histopathologic features, which may be associated with aggressive clinical behavior, include significant cellular atypia, one or more mitoses per 10 high-power fields, an increased proportion of spindled cells, focal necrosis, and metaplastic bone formation. Because of the intermediate malignant potential of epithelioid hemangioendothelioma, complete tumor resection is recommended for intraoral lesions.