Cytologic study of Noninvasive intraductal papillary-mucinous carcinoma of the pancreas

OBJECTIVE: To examine the cytologic features of non-invasive intraductal papillary-mucinous carcinoma (IPMC) in an attempt to differentiate it cytologically from hyperplasia, invasive IPMC and invasive ductal adenocarinoma (IDA). STUDY DESIGN: Tumor samples from 23 patients clinically diagnosed with a mucin-producing tumor of the pancreas, including 10 cases of hyperplasia, 10 non-invasive IPMCs and 3 invasive IPMCs, and tumor samples from 21 patients with IDA, were examined cytologically. Cytologic specimens were obtained in various ways, such as by fine needle aspiration, imprint, brushing, vinyl tube aspiration and aspiration from a cannula at endoscopic retrograde cholangiopancreatography. RESULTS: Cytologically, all 10 noninvasive IPMCs exhibited clearly defined cytoplasmic boundaries (+1, ++ 4, +++ 5) and mainly small nuclei (++ 7, +++ 3), with nuclear size and cytoplasm similar to those of hyperplastic cells, and irregular chromatin distribution (+ 2, ++ 8) and prominent nucleoli (-2, + 4, ++ 3, +++ 1), all atypical nuclear features similar to those of invasive IPMC or IDA. There also were small papillary cohesive clusters (- 1, + 2, ++ 4, +++ 3) and euchromatin (+ 1, ++ 1, +++ 8), which were found only in IPMCs. CONCLUSION: The cytologic features of small, malignant nuclei and small papillary cohesive clusters are suggestive of noninvasive IPMC. Furthermore, the addition of clearly defined cell borders and euchromatin and the presence of some goblet cells are more strongly suggestive of noninvasive IPMC.