Endoscopic Ultrasound-based Approach in the Diagnosis and Treatment for Pancreatic Cystic Lesions

The accurate diagnosis of pancreatic cystic lesions (PCLs) is important because they determine the strategy of treatment or follow-up. Endoscopic ultrasound (EUS) has been widely used in diagnosis and treatment of PCLs. EUS can be used to obtain additional information in the case of an indeterminate cyst on computed tomography or magnetic resonance imaging, or in case of showing a worrisome feature. Contrastenhanced EUS showed highly accurate for differential diagnosing of non-neoplastic cysts from neoplastic cyst, and it also useful for distinguishing mural nodules from mucin. EUS-guided fine needle aspiration can be used to analyze cytology, chemistry, and molecular markers in cystic fluid if there is insufficient evidence for the diagnosis by non-invasive modalities. Needle-based confocal laser endomicroscopy allows real time diagnosis of PCLs with good accuracy during EUS-guided fine needle aspiration by subcellular level imaging. Through-the-needle cystoscopy or through-the-needle forceps biopsy are also attempted in these days but the evidence for its effectiveness is insufficient. EUS-guided ablation procedures are emerging as a minimally invasive therapeutic methods for unmet needs in dichotomous treatment policy for PCLs. Large long-term follow-up observational studies have been reported on the feasibility and efficacy of EUS-guided ablation for PCLs with ethanol or in combination with chemoagent. Further study for the actual treatment effects or real clinical benefit would be needed. The use of EUS in the diagnosis and treatment of PCLs is expected to make much progress in the future.