Clinical Utility of Intracystic Glucose Levels in Differentiating Mucinous From Non-mucinous Pancreatic Cysts

Abstract

Introduction: To determine the utility of intracystic glucose levels in differentiating mucinous from nonmucinous pancreatic cysts. Compare the sensitivity and specificity of intracystic glucose versus carcinoembrogenic antigen (CEA) levels in differentiating mucinous from non-mucinous pancreatic cysts. Methods: A total of 17 subjects were included in the analysis. Average age was 66±14 years and 65% were female. Subjects were considered to have mucinous pancreatic cysts based on incidental finding of cyst(s) on MRI, ductal communication suggestive of IPMN, absence of prior history of pancreatitis, EUS features, and cyst fluid analysis and CEA levels. All patients with pseudocysts had documented prior episode of pancreatitis within past 6 months with imaging (CT/MRI) demonstrating new onset pancreatic cystic lesion. These patients had corroborating cyst fluid analysis and CEA levels. In addition, sensitivity and specificity of glucose levels of 2 mg/dL or less, glucose levels of 21 mg/dL or less, and CEA >184 ng/mL were estimated. Results: Intracyst glucose levels ranged from <2 to 121 mg/dL with a mean of 23.5±33.4 mg/dL; 53% had glucose levels ≥2 mg/dL. Patients with non mucinous cysts (pseudocysts) had higher levels of intracystic glucose. Differentiation of mucinous from non-mucinous pancreatic cysts based on intracyst glucose levels was found to be excellent with an AUC of 0.87 (95% CI 0.66, 1.0). Differentiation based on CEA levels was not as good (AUC 0.70; 95% CI 0.45, 0.96) and was not found to be significantly better than flipping a coin. A cutoff of 21 mg/dL or less would provide 100% sensitivity and 83% specificity (Table 1). CEA ≥184 ng/mL on the other had has a sensitivity of only 36% and a specificity of 100%. Using a combination of glucose ≤21 or CEA ≥184 does not improve diagnosis (100% sensitivity and 83% specificity as well).Table 1: Validity of CEA Intracystic Glucose Levels for Differentiating Mucinous From Nonmucinous CystsConclusion: Non-mucinous pancreatic cysts tend to have higher intracystic glucose level. High intracystic glucose level (>21 ng/mL) appears to have a high sensitivity and specificity in differentiating mucinous from non-mucinous pancreatic cysts. This simple, inexpensive test can aid in the evaluation of pancreatic cystic lesions which often pose a diagnostic conundrum.