Features of Chronic Pancreatitis and Associated Masses: A Focus on Endosonography

EUS is highly accurate in the diagnosis of chronic pancreatitis. Pancreatic calcifications or five or more endosonographic criteria are consistent with chronic pancreatitis. Less than three criteria essentially rules out chronic pancreatitis. Three or four criteria are the best overall cutoffs. The number of criteria is used to estimate the likelihood of pancreatitis (i.e. low/medium/high), and is not recommended to stage the severity (i.e. mild/moderate/severe) of disease. Obtaining histology by FNA is not recommended in all patients with chronic pancreatitis changes. EUS is useful in distinguishing inflammatory from malignant masses in the pancreas. FNA is often not required as the EUS appearance of inflammatory changes alone or bulkiness without any perceptible mass has good negative predictive value. In indeterminate masses, FNA for cytology is recommended. Follow-up imaging after one to two months can be performed to catch the rare EUS false-negatives, and confirm resolution or stability of inflammatory masses.