Heterotopic Pancreatic Tissue of the Stomach: Report of Three Cases and Consideration of Its Histogenesis.

Heterotopic pancreatic tissue of the stomach is a rare condition. The author herein reports three cases of heterotopic pancreatic of the stomach. The three cases were found in the 8,154 gastric specimens (biopsy 6,122 cases, gastrectomy 2,032 cases) of our pathology laboratory; the frequency was 0.04%. The first case was a 57-year-old woman who presented with epigastralgia. Endoscopic examination revealed a submucosal tumor in the body of the stomach. Partial gastrectomy was performed. Histologically, the lesion measured 25 × 20 × 25 mm and was submucosal heterotopic pancreatic tissue with hemorrhage and cystic changes. It was composed of acinar cells, ducts, and islets (Heinrich type I). The second case was a 57-year-old man without symptoms. Endoscopic examination revealed a submucosal tumor, and biopsy was taken. The biopsy showed heterotopic pancreatic tissue in the mucosa. It consisted of acinar cells and ducts (Heinrich type II). The third case was a 54-year-old woman without symptoms. Endoscopic examination showed chronic gastritis, and biopsy was obtained. The biopsy revealed heterotopic pancreatic tissue in the mucosa. It consisted of acinar cells and ducts (Heinrich type II). The first case appears to be a true heterotopic pancreas of congenital abnormality. The second and third cases seem to be heterotopic pancreatic tissues of congenital anomaly of the gastric mucosa. The histogenesis of heterotopic pancreatic tissue is discussed.