Cytology from pancreatic cysts has marginal utility in surgical decision-making

Preoperative diagnosis of pancreatic cystic neoplasms is problematic. We evaluated our experience with endoscopic ultrasound (EUS) to determine the utility of fine-needle aspiration cytology (FNAC) in surgical decision-making.

Patients evaluated for pancreatic cysts with EUS fine-needle aspiration (FNA) from 3/1996-10/2003 were included. Patients undergoing both preoperative EUS-FNA and pancreatic resection were identified. FNAC read as a mucinous cystic neoplasm (MCN), suspicious for neoplasia, or mucinous epithelial/atypical cells were classified as "concerning." Cytology with no malignant cells was negative. FNAC read as indeterminate, atypical cells of undetermined significance, or possible contamination was nondiagnostic.

Of 95 patients evaluated with EUS FNAC, 29 underwent resection. On final pathology, 7/29 lesions (24%) were malignant [two neuroendocrine tumors, three adenocarcinomas, one invasive intraductal papillary mucinous neoplasm (IPMN), and one metastatic uterine tumor], 4/29 (14%) were benign (three serous cystadenomas and one chronic pancreatitis), and 18/29 (62%) were premalignant (ten MCNs and eight IPMNs). Seven patients had concerning FNAC. All seven harbored malignant or premalignant lesions. Nine patients had negative FNAC: three (33%) with benign lesions and six (67%) with premalignant lesions. Thirteen of the 29 patients (45%) had nondiagnostic FNAC with 12/13 (92%) harboring a malignant or premalignant lesion. Sensitivity, specificity, positive predictive value, and negative predictive value were 28%, 100%, 100%, and 18%, respectively.

The decision to proceed with nonoperative management should not be based on a negative or nondiagnostic FNAC alone, as 67% of negative and 92% of nondiagnostic specimens were associated with malignant or premalignant pathology.