High risk of acute pancreatitis after endoscopic ultrasound-guided fine needle aspiration of side branch intraductal papillary mucinous neoplasms.

BACKGROUND AND OBJECTIVES: Data on the risk of acute pancreatitis following endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of pancreatic cystic lesions are limited. The aim of our study was to evaluate the frequency of acute pancreatitis after EUS-FNA of pancreatic cysts and solid lesions, and determine whether there was a difference in pancreatitis risk in patients with side branch intraductal papillary mucinous neoplasms (SB-IPMN). PATIENTS AND METHODS: A retrospective review of patients who underwent EUS-FNA of pancreatic cysts and solid lesions was performed. The primary outcome measure was development of acute pancreatitis after EUS-FNA. Factors associated with acute pancreatitis were examined by statistical analysis to determine independent predictors of acute pancreatitis. Statistical significance was determined at a P ≤ 0.05. RESULTS: We identified 186 patients with pancreatic cystic lesions and 557 with solid lesions in which EUS-FNA was performed. The median size of the cysts was 19 mm (range: 10-66 mm). There were 37 IPMNs, 33 mucinous cystic neoplasms, 58 serous cysts and 46 pseudocysts and 12 solid-cystic ductal carcinomas. The majority of patients (75%) with solid lesions were diagnosed with adenocarcinoma. Patients with pancreatic cysts had a statistically greater frequency of developing pancreatitis after EUS-FNA when compared to those with solid lesions (2.6% vs. 0.36% respectively; P = 0.13). In patients with cysts, there were no statistically significant differences between the two groups (with and without pancreatitis) with regard to a cyst location, size of the cyst, and number of needle passes or trainee involvement. Patients with SB-IPMN had a statistically higher frequency of pancreatitis after EUS-FNA compared to those with other cyst types (8% vs. 1.3% respectively; odds ratio = 6.4, 95% confidence intervals = 1.0-40.3, P = 0.05). DISCUSSION: Patients with SB-IPMN are at a higher risk of developing acute pancreatitis after a EUS-FNA. Alternative means of diagnosis such as magnetic resonance cholangiopancreatogram might be necessary to avoid risk of EUS-FNA.