The study schema is shown in Figure 4. (A) All patients referred to one of the participating academic centers for EUS evaluation of the PCL will be enrolled in the protocol if they satisfy inclusion criteria. Patient consent will be obtained during the clinic visit or prior to their EUS. EUS-guided nCLE imaging is first performed (B) followed by EUS-guided FNA and aspiration of cyst fluid. The cyst fluid is analyzed for CEA and cytology. As per institutional standard of care, the cyst fluid is also sent for molecular analysis. The results of the cyst fluid molecular analysis (B) will be utilized for the most likely diagnosis. Based on institutional multidisciplinary tumor board meetings, surgery is performed as indicated (C). Surgical histopathology serves as "gold standard" for diagnosis. It is anticipated that the majority of patients will undergo surgical resection after their EUS.

Inclusion Criteria:

• Patient age 18 years or older
• All patients referred for EUS-FNA of accessible PCL where surgery is contemplated
• Minimum cyst size should be ≥ 2.0 cm as determined by prior cross-sectional imaging studies

Exclusion Criteria:

• Unable to obtain informed consent
• Unable to tolerate the procedure
• Women with known pregnancy at time of procedure
• Patient age less than 18 years
• Bleeding diathesis
• Known allergy to fluorescein
• Prior pancreatic cancer
• Prior pancreatic surgery

Subjects for this study will be identified from patients referred for diagnostic EUS-FNA of PCLs for a non-study indication by a physician responsible for their care (i.e., gastroenterologists, oncologists, general internists, and surgeons) either at the primary study center.