A case of solitary fibrous tumor from the greater omentum resected via laparoscopic surgery

Solitary fibrous tumor (SFT) are relatively rare neoplasms that usually arise in the thoracic cavity in adults. Although many cases of extrathoracic SFT have been recently reported, SFT from the omentum is rare. A 32-year-old woman consulted a gynecologist complaining of irregular vaginal bleeding. Magnetic resonance imaging (MRI) revealed a tumor in the omentum, and the patient was admitted to our department. The patient underwent laparoscopic tumorectomy. The tumor size was 48×35×30 mm, and grayish-white nodules were observed. Histological examination showed hyperplastic spindle-shaped tumor cells with a pattern-less arrangement. Immunohistochemical staining showed the tumor was positive for CD34 and bcl-2, slightly positive for alpha smooth muscle actin (α-SMA), and negative for S-100 and c-kit. Accordingly, a diagnosis of SFT was made. The patient has not shown any recurrence 12 months after surgery. Most SFTs are benign, although there are some reports of recurring tumors. There are no clear guidelines for the treatment of SFT because of its rarity. Therefore, close long-term follow-up should be performed.