Objectives: Endoscopic ultrasound-guided fine-needle aspiration (FNA) is now widely used as a primary tool to diagnose pancreatic neoplasms. However, criteria that can reduce the risk of overdiagnosing pancreatic adenocarcinoma by FNA have not been adequately defined in the literature. This study aims to identify characteristic cytomorphological features that are helpful in distinguishing pancreatic adenocarcinoma from its mimics. Study Design: Five false-positive FNA cases (group A) diagnosed as adenocarcinoma (4 cases) and suspicious for adenocarcinoma (1 case) by FNA, were identified by searching our laboratory information system. Cytomorphological features of group A cases were compared to 12 true-positive, histologically confirmed FNA cases (group B). Results: Subsequent histological follow-ups of 5 misdiagnosed FNA cases showed 2 cases of intraductal papillary mucinous neoplasm with focal high-grade dysplasia, 1 case attributed to tumor contamination from a gastroesophageal junction adenocarcinoma, and 2 cases of pancreatic intraepithelial neoplasia (PanIN1/reactive change and PanIN2, respectively). Cytomorphological features present in both groups A and B included nuclear enlargement/overlapping, mild to moderate anisonucleosis, granular chromatin and prominent nucleoli. However, 1 or more of these 4 characteristic morphological features such as 3-dimensional cluster with cell disorientation, isolated malignant cells, irregular nuclear contour/nuclear grooves/notches (≥5% atypical cell population), and marked nuclear size variation 1:4 or higher was mainly present in adenocarcinoma. Conclusions: A combination of at least 2 of these 4 characteristic cytomorphological features needs to be present before rendering an unequivocal diagnosis of adenocarcinoma. Using these strict cytological criteria would have eliminated these false-positive diagnoses.

Keywords:
Pancreatic adenocarcinoma, Cytology smears, Endoscopic ultrasound, Fine-needle aspiration, Diagnostic pitfall
1.
Jemal A, Siegel R, Ward E, Hao Y, Xu J, Thun MJ: Cancer statistics, 2009. CA Cancer J Clin 2009;59:225-249.
2.
Distler M, Aust D, Weitz J, Pilarsky C, Grutzmann R: Precursor lesions for sporadic pancreatic cancer: PanIN, IPMN, and MCN. Biomed Res Int 2014;2014:474905.
3.
Singh M, Maitra A: Precursor lesions of pancreatic cancer: molecular pathology and clinical implications. Pancreatology 2007;7:9-19.
4.
Nelsen EM, Buehler D, Soni AV, Gopal DV: Endoscopic ultrasound in the evaluation of pancreatic neoplasms - solid and cystic: a review. World J Gastrointest Endosc 2015;7:318-327.
5.
Volmar KE, Vollmer RT, Jowell PS, Nelson RC, Xie HB: Pancreatic FNA in 1,000 cases: a comparison of imaging modalities. Gastrointest Endosc 2005;61:854-861.
6.
Chen J, Yang R, Lu Y, Xia Y, Zhou H: Diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration for solid pancreatic lesion: a systematic review. J Cancer Res Clin Oncol 2012;138:1433-1441.
7.
Jarboe EA, Layfield LJ: Cytologic features of pancreatic intraepithelial neoplasia and pancreatitis: potential pitfalls in the diagnosis of pancreatic ductal carcinoma. Diagn Cytopathol 2011;39:575-581.
8.
Layfield LJ, Cramer H: Fine-needle aspiration cytology of intraductal papillary-mucinous tumors: a retrospective analysis. Diagn Cytopathol 2005;32:16-20.
9.
Stelow EB, Bardales RH, Stanley MW: Pitfalls in endoscopic ultrasound-guided fine-needle aspiration and how to avoid them. Adv Anat Pathol 2005;12:62-73.
10.
Chen S, Wang X, Lin J: Fine needle aspiration of oncocytic variants of pancreatic neuroendocrine tumor: a report of three misdiagnosed cases. Acta Cytol 2014;58:131-137.
11.
Mitchell ML, Carney CN: Cytologic criteria for the diagnosis of pancreatic carcinoma. Am J Clin Pathol 1985;83:171-176.
12.
Cohen MB, Egerter DP, Holly EA, Ahn DK, Miller TR: Pancreatic adenocarcinoma: regression analysis to identify improved cytologic criteria. Diagn Cytopathol 1991;7:341-345.
13.
Robins DB, Katz RL, Evans DB, Atkinson EN, Green L: Fine needle aspiration of the pancreas. In quest of accuracy. Acta Cytol 1995;39:1-10.
14.
Chen S, Lin J, Wang X, Wu HH, Cramer H: EUS-guided FNA cytology of pancreatic neuroendocrine tumour (PanNET): a retrospective study of 132 cases over an 18-year period in a single institution. Cytopathology 2014;25:396-403.
15.
Vigliar E, Troncone G, Bracale U, Iaccarino A, Napolitano V, Bellevicine C: CD10 is useful to identify gastrointestinal contamination in endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) cytology from pancreatic ductal adenocarcinoma. Cytopathology 2015;26:83-87.
© 2016 S. Karger AG, Basel
2016
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.