Accuracy of endoscopic ultrasound-guided fine needle aspiration cytology on the differentiation of malignant and benign pancreatic cystic lesions: a single-center experience.

OBJECTIVES: The aim was to compare the use of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in cytology and the biochemical analysis of cyst fluid, together with the size of the lesion in the differentiation between benign and malignant pancreatic cystic lesions.

METHODS: Data of patients who underwent EUS-FNA for pancreatic cystic lesions in our center from January 2006 to October 2010 were retrospectively analyzed. The diagnostic accuracy of EUS-FNA was determined.

RESULTS: Of the 56 patients, 37 (66.1%) had evaluable cytology for diagnosis and sufficient cyst fluid was available for biochemical analysis in 58.9% (33/56) of the patients. The sensitivity, specificity, positive predictive value and negative predictive value of EUS-FNA for detecting malignancy were 63%, 100%, 100% and 85%, respectively. EUS-FNA was the most accurate diagnostic method for differentiating malignant and benign pancreatic cystic lesions (88%). Cyst fluid carcinoembryonic antigen (CEA) > 365 ng/mL had a sensitivity of 100% for the detection of malignant cystic lesions.

CONCLUSIONS: Although the rate of insufficient cyst fluid aspiration is high, the combination of cytological evaluation and CEA analysis of cyst fluid obtained by EUS-FNA is accurate in differentiating malignant cystic lesions from benign ones. Safe techniques are essential to improve the yield of cyst fluid aspiration by EUS.