Evaluating the Number of Passes Required for Diagnostic Cell Block During EUS-FNA of Solid Pancreatic Mass Lesions

This study will test the amount of tissue, called "cell block", obtained from your pancreas. Patients who are asked to participate in this study have a growth (mass) in the pancreas that needs a biopsy so a diagnosis can be made. Although we usually perform 2 to 4 passes (number of times the doctor biopsies the mass), at this time we do not know the ideal number of passes needed to obtain adequate amount of tissue for making a diagnosis. The purpose of this study is to compare the amount of tissue obtained with 2 passes versus 4 passes.

Primary Aim: To compare the number of passes required for obtaining adequate cell block material during EUS-guided FNA of solid pancreatic mass lesions. Primary Research Hypothesis: More specimen is required to obtain definitive diagnosis on cell block. This translates to less need for repeat procedures (due to nondiagnostic index procedure due to inadequate FNA passes), prompt treatment to patients and better use of health care resources. Therefore, we will be comparing 2 versus 4 FNA passes to determine which number of FNA pases will yield an adequate diagnostic cell block. Secondary Aims: To compare the rate of complications when performing 2 versus 4 EUS-FNA passes of solid pancreatic mass lesions. Secondary Research Hypothesis: EUS-guided FNA is a safe procedure with a complication rate of \< 1%. By performing more (four) NA passes one is likely to yield a better quality cell block while at the same time without compromising patient safety.