Squamous-lined cysts of the pancreas: Lymphoepithelial cysts, dermoid cysts (teratomas), and accessory-splenic epidermoid cysts

In the pancreas, 3 types of morphologically similar lesions may present as "squamous cysts": Lymphoepithelial cysts, dermoid cysts (monodermal teratom as), and epidermoid cysts in intrapancreatic accessory spleen. Lymphoepithe lial cysts (LECs) are seen predominantly in men (M/F: 4/1) and in adulthood (mean age, 56, and range, 35 to 74 years). They may occur at any site of t he organ (head, body, or fail). LECs are well-delineated cysts that may be multilocular (60%) or unilocular (40%), and they are characterized microsco pically by stratified squamous epithelium surrounded by a band of mature ly mphoid tissue with intervening well-formed germinal centers. Solid lymphoep ithelial clusters are seldom seen. The pathogenesis of LECs is unclear clin ical diseases that are known to be associated with their counterparts in th e salivary glands such as Sjogren disease or human immunodeficiency virus h ave not been documented for the LECs of the pancreas. The second type of sq uamous-lined cyst in the pancreas is the epidermoid cyst arising in intrapa ncreatic accessory spleen. These are located almost exclusively in the tail of the pancreas, in the fourth decade of life (mean age = 38). Their mean size is 4.5 cm [range, 2.3 to 6.5). In some cases, the cyst lining may be p artly mucinous. Dermoid cysts of the pancreas are also rare. The cases that appear to he true dermoid cysts occur in a younger age group (mean age, 23 , range, 2 to 53 years), and in contrast with LEG, there is no gender predo minance. Mucinous epithelium, respiratory-type mucosa and sebaceous units a re more readily identifiable in dermoid cysts, and they may contain hair. S ubepithelial lymphoid tissue is not a feature. They are sometimes complicat ed by suppurative infections. The Importance of these lesions is in their d istinction from other cystic neoplasms especially mucinous cystic tumors, C opyright (C) 2000 by W.B. Saunders Company.