[A Case of Small Intestinal GIST Diagnosed by Intussusception]

The patient was a 34-year-old female. She consulted our hospital with epigastric pain. Abdominal computed tomography (CT)revealed a small intestinal tumor, measuring 30 mm in diameter, with contrast effects. For detailed examination, enteroscopy was scheduled, but abdominal pain suddenly occurred. CT showed marked dilatation of the small intestine and intussusception, and emergency surgery was performed on the same day. Intussusception was observed on the anal side 70 cm from Treitz' ligament. The intestinal wall was black, and fissures of the serosa were partially noted. It was difficult to release the intussusception, and a 55 cm area of the jejunum involving the site of intussusception was resected. The patient was discharged on the 8th postoperative day. At the tip of the intussusception, a submucosal tumor measuring 25 mm in maximum diameter was present. Pathologically, the proliferation of spindle-shaped cells originating from the muscularis propria was observed, comprising an intricate structure. On immunostaining, KIT-positive and CD34, S-100, α-SMA-negative reactions were detected, leading to the diagnosis of a gastrointestinal stromal tumor(GIST). Nuclear divisions were noted in <5/50 visual fields. According to the risk classification, the risk was evaluated as low. The patient is being followed-up in accordance with guidelines.