Evaluation of Image-guided Brushing of Pancreatic Cyst Wall in Diagnosis of Cystic Pancreatic Tumors

Patients who meet the inclusion and exclusion criteria will be offered the study and those who consent will undergo Endoscopic Ultrasound (EUS) evaluation. All patients who consent to the study will undergo Endoscopic Ultrasound guided fine needle aspiration (EUS-FNA) and EUS guided EchoBrush. All patients will receive the recommended standard antibiotic prophylaxis (Ciprofloxacin 400 mg IV given 30 minutes prior to EUS) that is used prior to EUS-FNA of cystic pancreatic lesions and a prescription for oral Ciprofloxacin for 5 days post procedure (standard of care). Participants with pancreatic cysts that are \>10 mm but under 25 mm: These patients will undergo standard EUS-FNA of cyst fluid. From the first 19 participants, 0.5cc of aspirated cyst fluid will be sent for Proteomic analysis and the rest for cytology. EUS guided EchoBrush of the cyst wall will not be performed in this group of patients. Participants with pancreatic cysts that are \> 25 mm will undergo EUS guided Echobrush sampling of the cyst wall at the same time they undergo EUS-FNA. This will be done using the standard technique that is described below. EUS guided cyst wall brushing and residual fluid aspirated after lavage with 2 cc of sterile normal saline The tip of the Echobrush and the saline used to lavage the cyst will be placed in the same specimen jar (Specimen 2) based on the discussion with published experts on the EchoBrush technique. It should be noted that the pancreatic cyst will be punctured with the 19G FNA needle only once to obtain the specimens mentioned above. A single pass with EUS-FNA is the standard of care for pancreatic cysts and this study does not alter standard of care. It should be noted that the two groups represent two samples from the same patient and same cystic lesion. Therefore each patient will serve as their own internal control. All patients will be considered for surgical resection. Patients who do not undergo surgical resection will be followed up per standard of care.