Solitary fibrous tumor of the tongue: report of a case with immunohistochemical and ultrastructural studies.

Solitary fibrous tumors are rare in extrapleural sites and extremely rare in the oral cavity. We report a case of a solitary fibrous tumor arising from the tongue of a 70-year-old woman. The tumor measured 1.6 cm in maximum diameter and consists of spindle-shaped cells distributed in a haphazard pattern. Immunohistochemical studies show strong positivity for CD34 and bcl-2, and weak positivity for desmin. Smooth muscle actin and S-100 protein are negative. Electron microscopy shows uniform neoplastic spindle cells with mesenchymal features. The differential diagnosis for spindle cell neoplasms in the tongue is discussed. Copyright 2002, Elsevier Science (USA). All rights reserved.