Gastric duplications are relatively rare, constituting approximately 4% to 10% of all gastrointestinal duplications and having a male-female ratio of 2:1.1,2Several theories explain the embryonic development of gastric duplications, but no single theory adequately explains all types of duplications. In 1959, Rowling3proposed 3 morphologic criteria for the correct diagnosis of gastric duplication cysts. First, the cyst must be attached to the stomach and contiguous with its wall. Second, the cyst must be surrounded by at least 1 coat of smooth muscle, fusing with the muscularis propria of the stomach. Third, the cyst must be lined with typical gastric mucosa. Most gastric duplications are noncommunicating, cystic in nature, and situated along the greater curvature.2Because of the unspecific clinical symptoms, gastric duplications are usually diagnosed by surgical means. Nevertheless, preoperative imaging may be helpful in determining the diagnosis. Plain films and barium studies may suggest a mass by impression or displacement signs, but ultrasonography is needed to assess the nature and size of the mass.4In the patient described, ultrasonography was also performed and showed a thick-walled cyst containing echogenic material. It was not clear, however, from which organ the cyst originated. As in other reports,4,5our computed tomographic scan suggested duplication cyst of the stomach but could not exclude pancreatic pseudocyst or omental cyst. Magnetic resonance images were able to show the cyst as being separate from the pancreas, thereby raising the suspicion for gastric duplication cyst. The final diagnosis was based on a combination of preoperative imaging and surgical and histologic findings, for which all are requisite.