Solitary fibrous tumor of the floor of the mouth.

BACKGROUND: A solitary fibrous tumor (SFT) of the oral cavity is an extremely rare entity. Its diagnosis is complicated because of its diverse morphology and similarity to other mesenchymal diseases. CASE REPORT: A rare case of SFT involving floor of the mouth is presented. The tumor was well circumscribed and almost spherical, measuring approximately 3 cm in diameter. Patient was submitted to biopsy and histopathologic examination showed a tumor composed of spindle to epithelioid cells showing pale to eosinophilic cytoplasm, oval or elongated nuclei with inconspicuous nucleoli. Tumor cells showed strong positivity for CD34, vimentin and Bcl-2. SFTs may present as a diagnostic challenge. The patient was followed for 8 years without recurrences. RESULTS: SFT is an uncommon disease in maxillofacial region; however it should be considered in the differential diagnosis of spindle cell neoplasms with oral manifestation. Only a few cases have been reported in the floor of mouth. We describe a new case of SFT arising at this location. Key words:Solitary fibrous tumors, mouth floor, oral diagnosis.