Solitary fibrous tumor of the oral cavity: a systematic review of the literature and a new clinicopathologic case report.

Background: Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm of fibroblastic differentiation, originally described in the pleura and subsequently documented at multiple extrapleural sites. Oral involvement is uncommon and may be diagnostically challenging because of its variable clinical presentation and overlapping spindle-cell morphology. Materials and methods: We report a palatal SFT with clinical, imaging, histopathological and immunohistochemical correlation. In parallel, a systematic review was conducted in PubMed, Scopus and Web of Science for studies published between January 2015 and December 2025. Case reports, case series and retrospective clinicopathologic studies describing primary oral SFT were included. Study selection followed PRISMA 2020 recommendations and methodological quality was appraised qualitatively using Joanna Briggs Institute (JBI) critical appraisal tools appropriate to each study design. Results: Twelve eligible studies were included, comprising 10 case reports and 2 retrospective series for a total of 30 previously published oral SFTs. Soft-tissue lesions predominated, and the buccal mucosa/cheek was the most common location, followed by the floor of the mouth, tongue, labial mucosa, retromolar pad and intraosseous mandible. Across the reviewed studies, oral SFTs typically presented as slow-growing, well-circumscribed nodules and showed a patternless spindle-cell proliferation in a collagenous to hyalinized stroma with branching staghorn-like vessels. Signal Transducer and Activator of Transcription 6 (STAT6) was the most informative confirmatory marker, while Cluster of Differentiation 34 (CD34), B-cell Lymphoma 2 (BCL2) and Cluster of Differentiation 99 (CD99) were supportive but less specific. Most lesions were managed by complete local excision and showed a favorable course. In the present case, diffuse nuclear STAT6 positivity together with CD34, CD99 and BCL2 expression supported the diagnosis of palatal SFT. Conclusion: Oral SFT is an uncommon but distinctive fibroblastic neoplasm that should be included in the differential diagnosis of spindle-cell lesions of the oral cavity. Diagnosis relies on integration of morphology with immunohistochemistry, particularly STAT6. Complete surgical excision with margin assessment remains the cornerstone of treatment, and a risk-adapted long-term follow-up strategy is advisable because rare recurrences may occur, particularly in intraosseous, margin-positive, or proliferatively active tumors. Systematic Review Registration: The systematic review was registered on Prospero with code ID 1358544.