Comparative yield of fine needle aspiration cytology, ampullary biopsy, and needle knife assisted biopsy in the diagnosis of nonulcerated periampullary tumors.

Aim: Periampullary tumors (PAT) are defined as tumors arising within 2 cm of the major duodenal papilla. Studies on yield of preoperative biopsy for nonulcerated PAT are scarce. Needle knife papillotomy-assisted biopsy (NKAB) may sample the deeper tissues and thereby increase the histologic yield.