S3262 Lymphoethelial Cyst of the Pancreas: A Case Study

Introduction: Lymphoepithelial cysts (LECs) of the pancreas are rare, benign, true cystic lesions characterized by squamous epithelium and dense lymphoid tissue. Despite their benign nature, LECs often mimic neoplastic pancreatic cysts radiographically, leading to diagnostic uncertainty and potentially unnecessary surgical intervention. Given their rarity, accounting for less than 0.5% of all pancreatic cysts, LECs are frequently overlooked in differential diagnoses. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is essential for diagnosis, cytological confirmation and guiding management. Case Description/Methods: A 64-year-old woman with a history of hypertension and depression presented with persistent nausea for over 1 year, unaccompanied by vomiting, abdominal pain, weight loss, or gastrointestinal bleeding. An initial abdominal and pelvic computed tomography scan was unremarkable. Subsequent evaluation, including esophagogastroduodenoscopy, colonoscopy, and a gastric emptying study, was non-diagnostic. Trials of antiemetics (ondansetron, promethazine, scopolamine) failed to relieve symptoms. Abdominal magnetic resonance imaging revealed an incidental 1.8 × 0.9 cm multiloculated cyst adjacent to the pancreatic tail, with no contrast enhancement. EUS identified a complex anechoic lesion measuring 17.9 × 17.1 mm near the pancreatic tail, and FNA yielded 3 mL of white, viscous fluid. Cytopathologic analysis showed stratified squamous epithelium with dense lymphoid tissue, consistent with an LEC. No elevated tumor markers or mucin were detected. The pancreas was noted to be shortened and malpositioned, likely due to congenital anomaly. The cyst was deemed unrelated to her symptoms, and conservative management with surveillance imaging was pursued. Discussion: Pancreatic LECs pose a diagnostic challenge due to their overlapping imaging features with mucinous cystic neoplasms (MCNs), serous cystic neoplasms (SCNs), and intraductal papillary mucinous neoplasms (IPMNs). However, cytology demonstrating squamous epithelium, keratinous debris, and lymphoid tissue, along with the absence of mucin, CEA, or amylase elevation, is diagnostic. A literature review reveals that most LECs are asymptomatic and identified incidentally. Management should be individualized, with conservative observation appropriate for confirmed benign lesions. This case reinforces the importance of recognizing LECs in the differential diagnosis to avoid overtreatment. Increased awareness and appropriate use of EUS-FNA can prevent unnecessary surgery while ensuring accurate diagnosis.