This study will test two different needles for performing a biopsy of the pancreas during endoscopic ultrasound (EUS) procedures. Patients who are asked to participate in this study have a growth in the pancreas measuring greater than 35mm that needs a biopsy so that a diagnosis can be made. The biopsy can be performed using either a 19 or 25-Gauge needle. The purpose of this study is to compare which of the two needles is better for performing biopsies of the pancreas on masses that are greater than 35mm.

Endoscopic Ultrasound-guided fine needle aspiration (EUS-FNA) can be performed using the 25, 22 or 19 gauge (G) needles. Randomized trials have shown that all three needles are safe and perform equally well. However, in a retrospective study, the diagnostic sensitivity of EUS-FNA for pancreatic masses that measured more than 35mm was less compared to smaller size masses. This is because larger size tumors have more necrosis and it is difficult to identify cancer cells in them to make a diagnosis. Therefore, more biopsies must be performed in larger size tumors to establish a diagnosis. In previous studies it has been shown that the larger 19G needles procure larger and better quality tissue. Therefore, our hypothesis is that, when a larger 19G needle is used to FNA tumors more than 35mm, a diagnosis can be achieved with fewer passes.

Inclusion Criteria:

All patients referred to Florida Hospital Endoscopy Unit for assessment of pancreatic mass lesions greater than 35 mm on computed tomography (CT) that require FNA.

Exclusion Criteria:

• Age < 19 years
• Unable to safely undergo EUS for any reason
• Coagulopathy (INR >1.6, Prothrombin Time >18secs, Thrombocytopenia <80,000 cells/ml)
• Unable to consent
• Non-English speaking patients
• Participation in any other clinical trial (excluding registries or databases)