Lymphoepithelial cyst and epidermoid cyst of the accessory spleen in the pancreas

We report here two rare cystic lesions, a lymphoepithelial cyst (LEC) and a n epidermoid cyst of the accessory spleen (ECAS) occurring in the pancreas. Histologically, the LEC was lined by stratified squamous epithelium and su rrounded by a layer of lymphoid tissue with germinal centers. The ECAS show ed similar histologic features with scattered lymphoid tissue, but splenic pulp tissue was present in the wall. In both cysts, some small pancreatic i slets and ducts were seen in the fibrous tissue surrounding the lymphoid la yer or the splenic pulp, respectively. The lining epithelia of the LEC and the ECAS, as well as those of retention cysts of the pancreas and epidermoi d cysts of the spleen used for comparison, were similarly positive with AE1 /3, CAM5.2, CK7, CK13, and carcinoembryonic antigen. CA19-9 was also detect ed in the epithelial cells of the LEG, the ECAS, and the retention cyst of the pancreas, but not in those of the splenic epidermoid or branchial cleft cysts used for comparison. These findings indicate that LECs and ECASs mig ht develop from the pancreatic ducts protruding into a lymph node or access ory spleen located in the pancreas, respectively. Some of both cysts might cause elevated levels of serum carcinoembryonic antigen and/or CA19-9 and s hould be distinguished from malignant cystic tumors.