Pancreatic cyst fluid analysis for differential diagnosis between benign and malignant lesions

The majority of pancreatic cysts are detected incidentally when abdominal imaging is performed during unrelated procedures. The aim of the present study was to assess the diagnostic utility and clinical value of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA 19-9) and amylase analysis in pancreatic cyst fluid. The study included 52 patients with pancreatic cystic lesions, who underwent fine-needle aspiration biopsy to collect cystic fluid for cytological and biochemical analysis. Cysts were classified as benign (simple cysts, pseudocysts and serous cystadenomas) in 36 patients or premalignant/malignant (mucinous cyst-adenomas, intraductal papillary mucinous neoplasm and cystadenocarcinomas) in 16 patients. CEA and CA 19-9 were elevated in patients with malignant cysts (238±12.5 ng/ml and 222±31.5 U/ml, respectively) compared with benign lesions (34.5±3.7 ng/ml and 18.5±1.9 U/ml, respectively; P<0.001). Based on these results, the sensitivity and specificity of CEA were 91.8 and 63.9% and of CA 19-9 were 81.3 and 69.4%, respectively. Mean amylase levels in benign lesions (27825.7±91.9 U/l) were higher compared with malignant pancreatic cysts (8359.2±32.7 U/l; P<0.05). Cyst fluid analysis may prove a safe and useful adjunct for the differential diagnosis of pancreatic cystic lesions. In the present study, promising results for CEA and CA 19-9 have been demonstrated, however, the clinical value of these molecules must be confirmed.