Grumous Within a Pancreatic Cyst: A Rare Case of Lymphoepithelial Cyst of the Pancreas Arising Within an Accessory Spleen

Abstract

Cystic pancreatic lesions are regularly encountered on imaging studies of patients. Pseudocysts are the most common cystic lesion of the pancreas, but true pancreatic cysts are often neoplastic in origin which makes their classification important. A 58 y.o. caucasian male with a past medical history of diabetes, hypertension, and bilateral Warthin's tumor removal was referred for evaluation after presenting with an incidental mass found on CT. The patients only symptoms prior to examination was an unintended weight loss of 24 pounds. There were no significant findings on physical exam. The patient underwent MRI of the abdomen which demonstrated a cystic mass abutting the distal pancreatic body, proximal pancreatic talon, and inferior margin of the gastric body. The patient underwent EUS and was found to have an anechoic cystic mass with intracystic hypoechoic round nodules. Under doppler guidance, fine needle aspirate biopsies were taken which demonstrated cystic contents with highly degenerated squamous epithelium and cholesterol crystals with mucinous-like cells suggestive of lymphoepithelial cysts. The patient was referred for surgery and received a distal pancreatectomy. Surgical pathology confirmed the presence of lymphoepithelial cells within the cystic mass. The patient was subsequently discharged without complication. One of the benign forms of cystic lesions of the pancreas, lymphoepithelial cysts, are characterized as being filled with keratinized material, lined by mature keratinizing squamous epithelium which is surrounded by lymphoid tissue containing a few lymphoid follicles.They can arise from any portion in the pancreas, and sometimes within an accessory intrapancreatic spleen.These cystic lesions have distinctive clinical and pathological features making their identification with a high degree of specificity important.Upon review of the literature there are approximately one hundred reported cases of lymphoepithelial cysts arising within the pancreas. As imaging studies produce more pancreatic lesions it is important to develop a broad differential diagnosis and to develop characterizations of these lesions through identification of various factors in order to obtain an accurate diagnosis without the need for surgical intervention. Further study of the pathogenesis and progression of lymphoepithelial cysts is needed to create more accurate guidelines for their management.Figure: Magnetic resonance Imaging with contrast enhancement demonstrating a 6.2 x 4.5 x 3.0 cm mass abutting the superior margin of the distal pancreatic body/proximal pancreatic tail and the inferior margin of the gastric body. On T1-weighted imaging, the lesion is predominantly T1 hyperintense with rounded areas of hypointensity. On T2-weighted imaging the lesion is predominantly T2 intermediate intensity with a few rounded areas of hypointense signal.Figure: Endoscopic ultrasound of the pancreas demonstrating a 22 mm x 42 mm anechoic cyst with intracystic hypoechoic round nodules abutting the tail of the pancreas. Multiple intracystic nodules, the largest measuring 19 mm x 24 mm are also demonstrated. The cyst was abutting the pancreas and gastric body and causing some displacement of distal body and tail of the pancreas.Figure: Surgical pathology of the lymphoepithelial cyst - arrow demonstrating a small portion of splenic parenchyma.