A report of three cases of exophytic gastrointestinal stromal tumor detected by transabdominal ultrasound.

Gastrointestinal stromal tumors (GISTs) are the most common submucosal tumors of the stomach. GISTs are often detected by esophagogastroduodenal endoscopy (EGD). However, the exophytic GIST type is relatively rare and difficult to detect by EGD. Most exophytic GISTs found are large and symptomatic. We present three cases with exophytic GISTs less than 5 cm in diameter detected by transabdominal ultrasound (TUS). All patients were asymptomatic and TUS revealed hypoechoic solid masses 2-3 cm in diameter between the stomach and left lobe of the liver. In contrast, no tumor in the stomach was detected by esophagogastroduodenal endoscopy. Endoscopic ultrasound and enhanced CT showed gastric tumors protruding outward. All three cases underwent partial gastrectomy, and the excised tumor was diagnosed as low-grade GIST. In conclusion, TUS can be a starting point for diagnosing exophytic GISTs of the stomach.