A 78-year-old man with acute appendicitis underwent computed tomography, which incidentally revealed a 70 mm-sized nodular lesion adherent to the stomach and the pancreas. Endoscopic ultrasonography ( EUS ) showed a solid mass with a heterogeneous hypoechoic texture, but could not reveal whether the lesion arose from the stomach or pancreas. Laparotomy was performed. A pedunculated mass was found arising from the lesser curvature of the stomach without involvement of the pancreas. The mass was excised and diagnosed as a GIST histopathologically. According to the literature, the mean ratio of the diameter of the stem / the tumor in pedunculated extragastric GISTs is 0.17. In our case, video review of EUS showed that the ratio was 0.05. This ratio and video review are helpful when diagnosing pedunculated extragastric GIST using EUS.
