Endoscopic Ultrasound-Based Evaluation of Pancreatic Cysts: New Invasive Modalities

Pancreatic cysts are a heterogenous group of lesions that can be differentiated into mucinous and non-mucinous cysts based on their malignant potential. Crosssectional imaging alone is inadequate to reliably distinguish between the two groups. Endoscopic ultrasound (EUS) and fine needle aspiration has been used for analysis of the cyst morphology and cyst fluid. Traditional markers such as fluid carcinoembryonic antigen and cytology have been useful particularly for the assessment of indeterminate cysts or those with high-risk features, but the overall diagnostic accuracy is still sub-par. As a result, new techniques have been described to improve the ability of EUS to risk stratify a pancreatic cyst. In this review, we describe some of the novel EUS‑based techniques in the evaluation of pancreatic cysts, namely needle-based confocal laser endomicroscopy, through the needle cystoscopy, and through the needle biopsy techniques.