Solitary Fibrous Tumor of the Paranasal Sinuses with Intracranial Extension: A Rare Case Report and Review of the Literature.

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms that were initially identified in the pleura. SFTs in the nasal or paranasal sinuses are especially rare. Most SFTs exhibit indolent behavior, with a low local recurrence rate. A 39-year-old man complained of bilateral nasal congestion, hyposmia, and occasional right eye tears six months prior to hospitalization. Based on MRI and CT imaging, a total gross surgical resection was achieved. Subsequently, postsurgical histopathological examinations were conducted. Under the microscope, pathological mitotic bodies were visible (<5 mitoses per 2 mm²). The immunohistochemical staining results revealed that tumor cells were positive for CD34, BCL-2, STAT-6, and Ki-67 (<5%) but negative for EMA, S-100, PR, GFAP, and SMA. Based on these findings, the patient was diagnosed with SFT.