Abstract
Heterotopic pancreas (HP), a rare condition that is generally asymptomatic, is an aberration in the developmental profile of the pancreas. While it can occur in any location in the gastrointestinal tract, it is most typically found in the antrum of the stomach and is usually wrongly considered to be a submucosal tumor (SMT). Despite advances in diagnostic modalities, a HP still poses a diagnostic dilemma to clinicians. Invasive surgery or endoscopic resection have often been inappropriately applied in cases of an ectopic pancreas due to the difficulty in distinguishing it from neoplastic SMTs, such as gastrointestinal stromal tumors (GISTs). The present study reports the unusual case of a middle-aged female with an SMT at the lesser curve of the mid-body of the stomach, which was initially diagnosed as a GIST through endoscopic ultrasonography and computed tomography. However, following removal by endoscopic submucosal dissection, this lesion was finally histopathologically confirmed as an HP. Therefore, although it is rare, the possibility of an HP should always be considered when diagnosing an extramucosal gastric mass. The precise pre-operative diagnosis of this entity may avoid unnecessary extensive treatment intervention.