Ectopic pancreas appearing as a giant gastric cyst mimicking gastric lymphangioma: a case report and a brief review

Abstract Background Ectopic pancreas (EP) is defined as pancreatic tissue that lacks anatomical or vascular communication with the normal body of the pancreas. Despite improvements in diagnostic endoscopy and imaging studies, differentiating ectopic pancreatic tissue from gastric submucosal diseases remains a challenge. Case presentation Here, we present a case of a 44-year-old woman with severe epigastric pain. Initially, gastric lymphangioma was highly suspected due to a well-demarcated protruding mass with a large size that occurred in the submucosal layer of the gastric antrum and appeared as a cystic lesion. The final correct diagnosis of gastric EP was made during surgery. Conclusion Gastric EP with serous oligocystic adenoma appearing as a giant gastric cyst is extremely rare. The difficulty of making an accurate diagnosis and differential diagnosis is highlighted, which may provide additional clinical experience for the diagnosis of EP with serous oligocystic adenoma in the stomach.