Lymphoepithelial cyst of the pancreas - No evidence for Epstein-Barr virus-related pathogenesis

Compared to pseudocyst formation after prior pancreatitis, true cysts of th e pancreas are rare. Pancreatic cysts with irregular wall components off a mucinous content raise the suspicion for the presence of a cystic neoplasm, and surgical resection is recommended. A case of a patient with a history of prostate cancer is described in whom a cyst of the pancreatic tail was d iscovered incidentally. Based on the radiographic features, which did not s upport the presence of a serous cystadenoma, a spleen-preserving distal pan createctomy was performed. Histologic features were characteristic for a ly mphoepithelial cyst (LEC) of the pancreas, lined with thinned squamous epit helium surrounded by benign lymphoid tissue. Since LECs of the parotid glan d, which are associated with acquired human immunodeficiency, are frequentl y related to Epstein-Barr virus (EBV) infection, EBV in situ hybridization was performed and did not reveal evidence for EBV. Twenty-eight instances o f pancreatic LECs have been reported, primarily affecting adult males, with out evidence of increased numbers of EBV-positive cells. The pathogenesis, differential diagnosis, and clinical implications of lymphoepithelial pancr eatic cysts are discussed.