Solitary fibrous tumor (SFT) is a fibroblastic neoplasm of uncertain biological origin that is rare in the tongue.

A 42-year-old woman presented with a painless, submucosal nodule in the tongue. Based on the clinical hypothesis of benign mesenchymal neoplasia, the lesion was excised, and the specimen was submitted for histopathological analysis. Microscopically, a proliferation of spindle cells with a patternless arrangement was observed, separated by dilated and angulated vascular spaces. Immunohistochemical analysis revealed positivity for CD34, CD99, Bcl-2, Ki-67 (< 5%), and negativity for S-100. Additionally, the tumor cells showed a positive nuclear reaction for STAT6. The diagnosis was a solitary fibrous tumor.

This report presents a case of SFT in the tongue, emphasizing its clinicopathological, microscopic, and immunohistochemical features.