Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms that are usually localized in the mesothelium of soft tissues. Although SFTs of pleural origin are common, SFTs arising in the small intestine are extremely rare, and there are few reports of laparoscopic resection of these tumors. A 74-year-old woman presented to her local physician with intermittent pain in the lower abdomen. Computed tomography showed a 25 mm mass in the ileum with extramural protrusion and small intestine capsule endoscopy showed a submucosal tumor-like elevation covered by normal mucosa. The diagnosis was ileal tumor, which was removed by laparoscopic partial resection of the small intestine. Macroscopically, the tumor was found to be a substantial mass within subplasmalemmal fatty tissue that had no continuity with the muscular layer. Histological analysis showed proliferation of homogeneous spindle-shaped cells against a background of fibrous stroma. Immunostaining was positive for STAT6 and negative for KIT, Dog1, and S100, and SFT was diagnosed. The tumor was low risk according to Demicco's risk classification. In conclusion, a less invasive laparoscopic procedure is preferable if the tumor can be resected completely without applying excessive external force that results in seeding of tumor cells in the abdominal cavity.
Keywords: Case report; Ileum; Laparoscopy; Small intestine; Solitary fibrous tumor.
© 2022. Japanese Society of Gastroenterology.