Solitary fibrous tumor (SFT), a mesenchymal fibroblastic tumor that was initially seen in the pleura, has recently been reported in extrapleural sites, including the oral cavity. Here we report a case of SFT arising in the tongue and review the literature. A 92-year-old man presented with a history of repeated tongue bites due to a nodular mass on the left side of the tongue. An elastic, movable mass measuring 25 × 20 mm was palpated under the smooth mucosa. Gadolinium-enhanced magnetic resonance imaging showed a homogeneously enhanced mass. Based on the clinical diagnosis of a benign tumor, the lesion was surgically excised with the patient under general anesthesia. Although there was marked swelling of the floor of the mouth on the day after surgery, the patient could eat a normal diet without difficulty 5 days after surgery. Histopathological examination of the tumor revealed spindle cells arranged haphazardly in a variable configuration between collagen strands. Immunohistochemical staining showed that the tumor cells were positive for CD34, bcl-2, and vimentin, leading to a diagnosis of SFT. He was the oldest among the reported Japanese cases of SFT in the oral cavity. There was no sign of recurrence or metastasis 3 years after surgery.
