Jejunal heterotopic pancreas containing high-grade pancreatic intraepithelial neoplasia (PanIN-3) : case report and literature review

[ABSTRACT] We here report a rare surgical case of heterotopic pancreas in the jejunum that contained high-grade pancreatic intraepithelial neoplasm (PanIN-3). When a sixty-four-year old man had a surgery for transverse colon cancer in our hospital, a subserosal mass was coincidentally found in the jejunum and was resected for pathological determination. The mass was Heinrich type-I heterotopic pancreas that contained irregular dilation of pancreatic ducts with moderate to severe atypia, so-called PanIN-3. It is reported that heterotopic pancreas can be found at approximately 0.5% of laparotomy, mostly without specific preoperative symptoms. Most of its pathological characteristics are benign, whereas, there are a few reports of its malignant cases. PanIN-containing heterotopic pancreas is very rare in the literature. However, its malignant alteration is thought to arise through PanIN or intraductal papillary mucinous neoplasm (IPMN) as the carcinogenesis of orthotopic pancreas.