Fine-needle aspiration cytology of intraductal papillary-mucinous tumors: a retrospective analysis.

Intraductal papillary-mucinous tumor (IPMT) of the pancreas has become the accepted terminology for a group of mucin-producing epithelial proliferations lying within ectatic segments of the main pancreatic duct or its large branches. These neoplasms generally are associated with an indolent course, characteristic endoscopic ultrasonographic (EUS) findings, and a variable histo- and cytomorphology ranging from hyperplasia to carcinoma. Cytological specimens obtained by endoscopic ultrasound-guided or percutaneous fine-needle aspiration (FNA) are characterized by a background containing abundant mucin in which are entrapped single or loosely cohesive clusters of neoplastic cells characteristically showing a goblet-cell morphology. The degree of nuclear atypia, cell crowding, and cell shape varies between smears within a single case and between cases. Cytomorphological examination, when coupled with EUS features, is accurate for the diagnosis of these lesions but often it underdiagnoses the grade of the neoplasm.