[A case of intraorbital solitary fibrous tumor resected successfully with preoperative arterial embolization].

The solitary fibrous tumor (SFT) is a rare spindle cell neoplasm derived from mesenchymal cells. It sometimes recurs clinically, and is categorized as an 'intermediate malignancy' tumor under the WHO (World Health Organization) classification of soft tissue tumors. Several studies have reported on intraorbital SFTs, but none of them has pointed out the utility of preoperative arterial embolization in the case of an intraorbital SFT. A 75-year-old man, who had received a dacryocystectomy for a benign tumor in the right lacrimal sac 30 years previously, visited our hospital complaining of lower eyelid swelling and lachrymation that had persisted for a year. CT and MRI revealed an intraorbital lesion, and the open biopsy specimen showed dense growth of spindle cells, which turned out to be an SFT by immunohistochemistry based on the findings. After preoperative embolization of the infraorbital artery, we removed the tumor with a skin incision on the lower rim of the orbit with little bleeding. The surgical specimen revealed that the tumor was close to a lacrimal canaliculus, which suggested the tumor originated from the lacrimal apparatus considering the patient's past history. He was followed up for three months without recurrences.