Intraorbital Solitary Fibrous Tumor Requiring Preoperative Embolization of Feeding Artery.

Solitary fibrous tumors (SFTs) are derived from mesenchymal cells and commonly develop in thoracoabdominal organs; however, their occurrence in orbit is rare. The first-choice treatment is to surgically remove as much of the SFT as possible; however, if total removal is not achieved, the recurrence rate is high, resulting in poor prognosis. A 42-year-old man presented with painless right-sided proptosis and diplopia 4 years ago. Orbital computed tomography revealed a right extraconal mass medial to the optic nerve, measuring 25 mm. Magnetic resonance imaging demonstrated iso-signal intensity on T1- and T2-weighted imaging, including flow-void signals. During biopsy of the intraorbital mass, which was performed by ophthalmologists 3 years earlier, difficulty with hemostasis occurred due to massive hemorrhage from the mass. The mass grew to reach a maximal diameter of 33 mm, resulting in referral to the authors' department. Diagnostic cerebral angiography revealed a hypervascular orbital tumor with multiple feeding arteries. To control intraoperative bleeding, the patient underwent preoperative endovascular embolization. Subsequently, the tumor was completely removed using a combination of microsurgical craniotomy and endoscopic endonasal approach, without the occurrence of massive intraoperative hemorrhage from the tumor. Postoperatively, his clinical course was uneventful except for the remaining preoperative diplopia. The tumor was diagnosed histologically as SFT and has not recurred for 8 months since surgery. Preoperative intravascular embolization of branches of the ophthalmic artery can be performed safely, resulting in excellent control of intraoperative bleeding and facilitating complete removal of SFT without additional complications.