Objective: Malignant effusions due to papillary thyroid carcinoma (PTC) are rare, but portend a poor prognosis. PTC metastases, although rare, most frequently occur in the lungs and bone. Therefore, differentiating thyroid etiology of malignant effusions from other sites becomes clinically significant in patient management. This study examines morphologic and immunocytochemical findings in 5 cases of malignant effusions with PTC involvement. Study Design: The electronic database at the University of Michigan was searched from January 1, 1995 to December 31, 2014 for malignant pleural effusions with PTC involvement. Clinicopathologic data were obtained from electronic medical records. Cytologic slides were reviewed. Results: Five cases of malignant effusions due to PTC were identified. Characteristic cytologic features of PTC, including ovoid nuclei, irregular nuclear contours, and psammomatous calcifications, were seen. However, the predominant cytologic feature observed was moderate amounts of delicate to vacuolated cytoplasm within the tumor cells. A review of immunocytochemistry demonstrated that all 5 cases showed patchy to diffuse TTF-1 positivity and diffuse positivity for Pax-8. Thyroglobulin only showed focal to patchy positivity in 3 of 5 cases. Conclusion: Given the morphologic features found in our case series, an immunocytochemical workup for the evaluation of involvement of an effusion by a thyroid primary is crucial for accurate diagnosis and appropriate clinical treatment.

Keywords:
Metastatic carcinoma, Papillary thyroid carcinoma, Malignant effusion, Immunocytochemistry
1.
Olson MT, Nuransoy A, Ali SZ: Malignant pleural effusion resulting from metastasis of thyroid primaries: a cytomorphological analysis. Acta Cytol 2013:57:177-183.
2.
Vassilopoulou-Sellin R, Sneige N: Pleural effusion in patients with differentiated papillary thyroid cancer. South Med J 1994:87:1111-1116.
3.
Vernon AN, Sheeler LR, Biscotti CV, Stoller JK: Pleural effusion resulting from metastatic papillary carcinoma of the thyroid. Chest 1992:101:1448-1450.
4.
Rosenstengel A, Lim EM, Millward M, Lee YG: A distinctive colour associated with high iodine content in malignant pleural effusion from metastatic papillary thyroid cancer: a case report. J Med Case Rep 2013:7:147.
5.
Takeshita J, Katakami N, Fujita S, Imai Y: Pleural metastases from papillary thyroid carcinoma mimicking mesothelioma. Intern Med 2014:53:163-164.
6.
Husain AN, Colby T, Ordonez N, et al: Guidelines for pathologic diagnosis of malignant mesothelioma: 2012 update of the consensus statement from the International Mesothelioma Interest Group. Arch Pathol Lab Med 2013;137:647-667.
7.
Ordonez NG: Application of mesothelin immunostaining in tumor diagnosis. Am J Surg Pathol 2003;27:1418-1428.
8.
Yaziji H, Battifora H, Barry TS, et al: Evaluation of 12 antibodies for distinguishing epithelioid mesothelioma from adenocarcinoma: identification of a three-antibody immunohistochemical panel with maximal sensitivity and specificity. Mod Pathol 2006;19:514-523.
9.
Bishop JA, Sharma R, Illei PB: Napsin A and thyroid transcription factor-1 expression in carcinomas of the lung, breast, pancreas, colon, kidney, thyroid, and malignant mesothelioma. Hum Pathol 2010;41:20-25.
10.
Cimino-Mathews A, Sharma R, Netto GJ: Diagnostic use of PAX8, CAIX, TTF-1, and TGB in metastatic renal cell carcinoma of the thyroid. Am J Surg Pathol 2011;35:757-761.
11.
Ye J, Hameed O, Findeis-Hosey JJ, et al: Diagnostic utility of PAX8, TTF-1, and Napsin A for discriminating metastatic carcinoma from primary adenocarcinoma of the lung. Biotech Histochem 2012;87:30-34.
12.
Turner BM, Cagle PT, Sainz IM, et al: Napsin A, a new marker for lung adenocarcinoma, is complementary and more sensitive and specific than thyroid transcription factor 1 in the differential diagnosis of primary pulmonary carcinoma: evaluation of 1,674 cases by tissue microarray. Arch Pathol Lab Med 2012;136:163-171.
13.
Chernock RD, El-Mofty SK, Becker N, et al: Napsin A expression in anaplastic, poorly differentiated, and micropapillary pattern thyroid carcinomas. Am J Surg Pathol 2013;37:1215-1222.
14.
Mukhopadhyay S, Katzenstein AA: Comparison of monoclonal Napsin A, polyclonal Napsin A, and TTF-1 for determining lung origin in metastatic adenocarcinomas. Am J Clin Pathol 2012;138:703-711.
© 2015 S. Karger AG, Basel
2015
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.