Adenocarcinoma of the small intestine arising from heterotopic gastric mucosa is extremely rare. In this report, we present the case of a 68-year-old woman who complained of abdominal pain, weight loss and subileus. Gross examination of resected small bowel revealed multiple flat polypous lesions with cysts in the ileal submucosa, one of which containing an ulcerated, stenosing tumour. On microscopic examination, an adenocarcinoma of the ileum arising from multifocal gastric heterotopia with secondary gastritis cystica profunda was diagnosed. Comparative genomic hybridization of the adenocarcinoma revealed chromosomal gains at 1q, 3q, 5p, 8q, 11p, 12p, 13q and losses at Xp, 4q, 8p, 10p, 14q, 17p, 20p, compatible with a high degree of genomic instability.
Keywords: Gastric heterotopia, Gastritis cystica profunda, Adenocarcinoma, Ileum, Comparative genomic hybridization