Gastric type III heterotopic pancreas presenting as adenomyoma in the antrum of the stomach: a case report

Although heterotopic pancreas usually occurs in the stomach and rarely presents as a submucosal tumor, an accurate preoperative diagnosis is often difficult because of the variety of clinical symptoms and findings depending on the size and location of the lesion. We experienced a case of gastric type III heterotopic pancreas presenting as a gastric adenomyoma in the antrum of the stomach. A 62-year-old woman visited a local hospital for epigastric discomfort. An esophagogastroduodenoscopy study indicated a submucosal tumor in the greater curvature of the gastric antrum. The patient underwent surgical resection of the tumor because it was enlarged. The histological sections of the resected specimen showed that the tumor was composed of ductular structures lined by tall columnar epithelia and a prominent smooth muscle stroma with no atypical cells. The tumor was compatible with Heinrich's type III heterotopic pancreas, which presented as an adenomyoma of the stomach. These findings provide useful histological features and some insight into a better understanding of the embryonic origin and development of adenomyoma and heterotopic pancreas in the antrum of the stomach.