Solitary Fibrous Tumor of the Nasal Vestibule: A Case Report.

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor defined by the NGFI-A binding protein 2 (NAB2)-signal transducer and activator of transcription 6 (STAT6) fusion gene and rarely arises in the sinonasal tract. An origin in the nasal vestibule is exceptionally rare; to our knowledge, there is only one previously documented case in the English literature. We report a 48-year-old man who presented with progressive right-sided nasal obstruction and external nasal deformity caused by a well-circumscribed, enhancing tumor occupying the nasal vestibule and extending to the inferior turbinate. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated a homogeneous, vascular-rich mass without bone erosion, and positron emission tomography-computed tomography (PET-CT) revealed mild fluorodeoxyglucose (FDG) uptake. The lesion was removed endoscopically via piecemeal resection due to the limited vestibular space. Histopathological examination showed a patternless spindle cell proliferation with collagen bundles and branching, staghorn vessels. Immunohistochemistry demonstrated diffuse nuclear STAT6 and CD34 positivity, confirming SFT, with a low Ki-67 labeling index of 5%, and no necrosis or significant mitotic activity. The patient recovered without postoperative complications and continued to be disease-free at the 12-month follow-up visit. To our knowledge, this case represents the second known example of an SFT originating in the nasal vestibule and highlights that even in anatomically constrained regions where en bloc excision is difficult, meticulous piecemeal endoscopic resection can achieve complete tumor clearance and favorable early outcomes. Long-term surveillance remains essential due to the potential for late recurrence.