Table of Contents
Pathology Research International
Volume 2011, Article ID 238693, 5 pages
http://dx.doi.org/10.4061/2011/238693
Case Report

Tumors Metastatic to Thyroid Neoplasms: A Case Report and Review of the Literature

1Department of Pathology, Creighton University Medical Center, Omaha, NE 68131, USA
2Division of Head and Neck Surgery, University of Nebraska Medical Center and Creighton University Medical Center, 42nd and Emile Street, Omaha, NE 68198, USA

Received 28 December 2010; Accepted 31 January 2011

Academic Editor: R. Montironi

Copyright © 2011 Todd M. Stevens et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Metastasis into a thyroid neoplasm—tumor-to-tumor metastasis—is exceedingly rare. We describe the 28th documented case of a tumor metastatic to a thyroid neoplasm and review the literature on tumor-to-tumor metastasis involving a thyroid neoplasm as recipient. All cases showed a recipient thyroid neoplasm with an abrupt transition to a morphologically distinct neoplasm. Metastasis into primary thyroid neoplasm was synchronous in 33% of cases and metachronous in 67%. Follicular adenoma was the most common recipient thyroid neoplasm overall (16/28), and papillary thyroid carcinoma was the most common malignant recipient neoplasm (9/28). Of the 9 recipient papillary carcinomas, 6 were follicular variants. Renal cell carcinoma was the most common neoplasm to metastasize to a primary thyroid neoplasm (9/28), followed by lung (6/28), breast (5/28), and colon (3/28) carcinoma. Tumor-to-tumor metastasis should be considered whenever a dimorphic pattern is encountered in a thyroid tumor.