Cystic lymphoepithelial lesions of the pancreas and peripancreatic region: report of two cases.

Two cases of an extremely rare cystic lymphoepithelial lesion of a lymph node associated with the pancreas are presented herein. The first patient was a 57-year-old woman with a serous cystoadenoma who underwent resection of the body and tail of pancreas, and the other patient was a 75-year-old woman with cancer of the papilla of Vater who underwent pylorus-preserving pancreatoduodenectomy. Both lesions were incidentally found during pathologic examination of lymph nodes from the peripancreatic region. Histologically, there were many scattered nests of the lymphoepithelial lesion in the lymphoid stroma, each of which was lined with stratified squamous epithelium. The pathological structure was found to resemble the lymphoepithelial lesion of the pancreas. Although the histogenesis is unknown, we hypothesize that the lesion might have arisen from squamous metaplasia of a benign epithelial inclusion such as the pancreatic duct of an ectopic pancreas in a peripancreatic lymph node. Therefore, a cystic lesion formed as a result of keratinization of the squamous epithelium with invasion into the pancreas could become a lymphoepithelial cyst of the pancreas.