Cyst Fluid Amylase and CEA Levels in the Differential Diagnosis of Pancreatic Cysts: A Single-Center Experience with Histologically Proven Cysts

Abstract

Objective Cyst fluid amylase is a potential marker for pseudocysts and intraductal papillary mucinous neoplasms (IPMN). This study aimed to evaluate the diagnostic role of cyst fluid amylase and to determine the optimal cutoff values of cyst fluid amylase and carcinoembryonic antigen (CEA) for the differential diagnosis of pancreatic cysts. Methods Based on the pancreatic cyst database at Massachusetts General Hospital, a total of 78 patients with histologically proven cysts [pancreatic pseudocyst (PP), n = 16; mucinous cystic neoplasm, mucinous cystic neoplasm (MCN), n = 22; IPMN, n = 40] were selected. Complete cyst fluid amylase and CEA values were analyzed. Results Thirty two of 78 patients were male with median age of 60.4 years (range, 24-84). Cyst diameter ranged from 5 to 130 mm. For cyst fluid amylase, there was significant difference between PP and MCN (median, 30,034.50 vs. 4,723.50 U/L; p < 0.05) or IPMN (30,034.50 vs. 1,585.00; p = 0.001), but no difference between MCN and IPMN. For cyst fluid CEA, there was a significant difference between PP and MCN (median, 26.00 vs. 627.50 ng/mL; p < 0.001) or IPMN (26.00 vs. 356.50; p < 0.001). Median amylase and CEA values were significantly different between PP and mucinous neoplasms (MCN/IPMN) (p < 0.01 and p < 0.001). Optimal cutoff values of 6,800 U/mL for amylase and 50 ng/mL for CEA correlated with the crossover of the sensitivity and specificity curves for differentiating PP and mucinous neoplasms. The overall accuracies of cyst fluid amylase and CEA were 69 and 85 %, respectively. Conclusions Cyst fluid amylase analysis does not differentiate between MCN and IPMN. The combination of cyst fluid CEA and amylase value may increase the diagnostic accuracy for differentiating mucinous neoplasms from pseudocysts.