Heterotopic pancreas of the stomach. Histogenesis and immunohistochemistry

A Case of Myoepithelial Hamartoma: Morphological Variation Supported by OCT4 Expression

In this report, we describe a patient with myoepithelial hamartoma, which is regarded as synonymous with adenomyosis and heterotopic pancreas. Endoscopy revealed a submucosal tumor in the antrum of the stomach. Subsequently, distal gastrectomy with Roux-en-Y reconstruction was performed. Histological findings of adenomyomatous lesion and heterotopic pancreatic tissue were observed in this lesion. The distribution of OCT4, which is a pluripotency marker, varied in each part.

Histopathological study using computer database of 10 000 consecutive gastric specimens: (1) benign conditions

Using a computer database, the author investigated the histopathology of 10 000 consecutive gastric specimens, taken in the last 12 years (2002–2013) at the pathology laboratory of a Japanese hospital. Re-observation of the already examined histological sections was done when the histological diagnosis and findings on the computer data base were not very obvious. The gastric specimens were identified as 8579 benign conditions and 1421 malignant lesions. The 8579 benign conditions were comprised almost normal stomach in 74 cases (0.9%), chronic gastritis in 4374 (51.0%), benign gastric peptic ulcer in 2195 (25.6%), foveolar hyperplastic polyp in 1004 (11.7%), fundic gland polyp in 421 (4.9%), adenoma in 487 (5.6%), heterotopic pancreas in 9 (0.1%), pancreatic acinar metaplasia (PAM) in 8 (0.1%), and amyloidosis in 7 (0.1%). Chronic gastritis showed lymphocytic infiltration and frequently showed erosions and intestinal metaplasia. Gastric peptic ulcer showed exudate, necrosis, active inflammation, and regenerative atypia of the epithelium. Foveolar hyperplastic polyp revealed 23 malignant changes and frequently showed dysplastic glands and intestinal metaplasia. Fundic gland polyp demonstrated cystic dilations of fundic gland ducts. Gastric adenoma showed adenomatous proliferation in the superficial mucosa and cystic dilation of the epithelium under the adenoma. Heterotopic pancreas was located in the submucosa and consisted of acinar cells, ducts, and occasionally islets. PAM was a tiny lesion in the mucosa and consisted of only pancreatic acinar cells. Amyloidosis was primary amyloidosis with positive reaction with Congo-red stain.

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.