Patients who have surgery either during Phase I or Phase II, will enter post-surgical surveillance (Phase III). Patients will be followed using a prospective periodic surveillance schedule according the consensus clinical guidelines with either CT or MRI to monitor for new or metachronous cystic neoplasms. Those who undergo surgery after surveillance in Phase II will continue with the imaging modality they were originally evaluated with prior to surgery.. Patients who develop symptoms or high-risk features on imaging will have a repeat EUS/FNA as well as imaging with the opposite axial imaging modality and will be referred for surgery if a suspicious lesion is detected. Samples will be collected prospectively for biomarker analysis. Cyst fluid, pancreatic juice and blood will be collected during EUS and blood will be collected yearly during the outpatient clinic visit. Patients will be followed for three years.