Cystic jejunal duplication with Heinrich's type I ectopic pancreas, incidentally discovered in a patient with pancreatic tail neoplasm.

The aim of this study was to present a case of enteric duplication cyst and criteria for a proper differential diagnosis. A 51-year-old male was hospitalized for pancreatic tail neoplasm and distal pancreatectomy with splenectomy was performed. During surgery, a jejunal cystic lesion was incidentally detected and jejunectomy was performed. Microscopically, the cyst was observed to be covered by Keratin 7/Keratin 20 positive intestinal type epithelium and the muscularis layer was shared by the cyst and adjacent jejunum, without a cleavage plane between the cyst wall and jejunal muscularis propria. In the deep muscularis propria, a Heinrich's type I ectopic pancreas was also noted. In the pancreatic tail, a low grade intraepithelial lesion (panIN-1a) was diagnosed. This case highlights the necessity for a correct differential diagnosis of such rare lesions. Roughly 30 cases of jejunal duplication cysts have been reported to date in the PubMed database.