A 68-year-old man visited the emergency room of our hospital with the complaint of sudden epistaxis. It was his first episode of epistaxis. A small reddish tumor was observed on the nasal septum using a nasal video scope. A computed tomography scan showed a small mass (about 5 mm) in the right nasal cavity that had arisen from the septal wall (Fig.
1). Although nasal packing was performed, oozing from the tumor continued. GPC was suspected based on findings of a histologic examination of the biopsy specimen, and the differential diagnosis included SFT. After 1 month, the patient was scheduled for an endonasal surgery. Pre-operative tumor embolization was not performed in light of the small size of the tumor. A reddish mass with a smooth surface extended from the high septum to the skull base. Tumor resection was designed with 5 mm margins, and resection was achieved using a Colorado Needle Scalpel (Fig.
2). Complete tumor dissection was achieved with ease. The blood loss was 10 mL, and operation time was 30 min. It was a subepithelial, well-delineated tumor, and the epithelium was partially eroded (Fig.
3a). The size of the tumor was 12 × 5 mm, and it histologically showed a uniform proliferation of oval-to-short spindle-shaped cells with slightly branching vascular structures (Fig.
3b). Stromal bleeding was also noted; however, no necrosis was observed. The tumor cells showed minimal cytologic atypia and there were an average of 3 mitoses in 10 high power fields (Fig.
3c). Tumor cells were diffusely and strongly positive for β-catenin nuclear staining (Fig.
3d), but negative for STAT6 (Fig.
3e). The MIB-1 labeling index was < 5% (Fig.
3f) and tumor cells were negative for CD34 and bcl-2. The surgical margin was negative for tumor cells. Genetic testing using DNA extracted from formalin-fixed paraffin embedded tissue revealed
CTNNB1 mutation (p.S33C) (Fig.
3g). Based on these findings, we diagnosed the patient with GPC.