A case of gastrointestinal stromal tumor of the stomach showing extragastric growth detected on abdominal ultrasound during a medical check-up

Abstract

In September 2019, a 36-year-old woman underwent abdominal ultrasound for a medical check-up at our hospital, and a mass measuring 38 mm in diameter was identified on the ventral side of the pancreatic body in contact with the stomach. Gastrointestinal radiography showed a submucosal tumor-like protrusion on the lesser curvature of the gastric angle. Computed tomography showed an extrinsic mass containing a cystic component with uneven contrast enhancement on the lesser curvature of the gastric angle. Upper gastrointestinal endoscopy showed a submucosal tumor measuring 30 mm in diameter on the lesser curvature of the gastric angle. Endoscopic ultrasound-guided fine-needle aspiration was performed, and the diagnosis of a gastrointestinal stromal tumor (GIST) was established. The patient then underwent laparoscopic partial gastrectomy. Histopathological examination showed that the tumor was positive for KIT and negative for CD34, with a mitotic count of 3/50HPF and an MIB-1 labeling index of 6.9%; thus, the tumor was classified as a low-risk GIST. Herein, abdominal ultrasound led to the detection and diagnosis of a GIST of the stomach showing extragastric growth.