Benign mucin containing pancreatic lesions are often perceived to represent malignant mucinous neoplasms in the pre operative work up. Pancreatic lymphoepithelial cysts (LEC) can be difficult to differentiate from malignant mucinous pancreatic lesions such as intraductal papillary mucinous neoplasm (IPMN) or mucinous cystadenoma due to similar cytological and radiological findings.
Half of LEC are diagnosed incidentally on CT whereas the remainder have nonspecific symptoms, such as abdominal pain, nausea and weight loss. It is difficult to preoperatively differentiate LEC from other pancreatic cysts such as IPMN and MCA due to similar radiological and pathological features. Half of all LEC are associated with raised CEA and CA 19.9 levels. Typical findings on CT include a hypoenhancing, anodular, noncalcified thin walled cystic lesion which can be multilocular or unilocular, peripancreatic or intrapancreatic. A well-circumscribed heterogeneous peri-pancreatic lesion visualized on endoscopic ultrasonography and the cytological presence of squamous cells with lymphoid follicles are usually diagnostic obviating the requirement for surgery, whereas the presence of mucin in LEC is an unusual and unexpected finding which can obscure the diagnosis.
Surgery is necessitated whenever pre-operative concerns for a mucinous pancreatic neoplasm is present. Due to the benign nature of LEC, the morbidity and mortality with pancreatic surgery is increasingly complex when such cysts can be managed non operatively.
We present the first case of a mucin containing LEC masquerading as a mucinous pancreatic neoplasm. This case report uncovers an exceedingly rare finding which we hope will lead to a greater understanding of the histological make up of LEC to improve preoperative characterization and differentiation from malignant pancreatic lesions.