Endoscopic ultrasound guided fine-needle aspiration and biopsy of pancreatic cysts

Pancreatic cystic lesions (PCLs) are often incidentally found on cross-sectional imaging. Long strides have been made in the past decade with improved quality and optics of cross-sectional imaging and endoscopic ultrasound (EUS), but a singular reliable test to appropriately characterize and risk-stratify PCLs has still eluded us. EUS allows high-resolution imaging of the pancreatic parenchyma and the ductal system, for assessment of PCL characteristics, with features concerning for malignancy and additionally provides an opportunity to sample the cyst to obtain fluid or cells for further diagnostic testing. This presents new sets of challenges, which include devising suitable equipment or needles and techniques for reliable and safe tissue acquisition, as well as provision of an adequate cytology or tissue sample to the pathologist, in order to arrive at an accurate diagnosis. This article will review the current role of EUS in the diagnosis and characterization of PCLs, with a focus on available strategies and pitfalls of cytology, cyst-fluid biomarkers, and biopsy acquisition techniques; and future directions to increase the yield and accuracy.