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Case Reports in Oncological Medicine
Volume 2013, Article ID 485025, 5 pages
http://dx.doi.org/10.1155/2013/485025
Case Report

Metastases of Renal Cell Carcinoma to the Thyroid Gland with Synchronous Benign and Malignant Follicular Cell-Derived Neoplasms

1Department of Respiratory Medicine, Clinical University Hospital, SERGAS, Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, 15706 Santiago de Compostela, Spain
2Department of Anatomic Pathology, Clinical University Hospital, SERGAS, Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, 15706 Santiago de Compostela, Spain
3Department of Medical Oncology, University Hospital Complex of Ourense, SERGAS, 32005 Ourense, Spain
4Department of Medical Oncology, Clinical University Hospital, SERGAS, Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, 15706 Santiago de Compostela, Spain

Received 28 February 2013; Accepted 27 March 2013

Academic Editors: K. Aogi, L. Beex, J. M. Buchanich, D. V. Jones, P. F. Lenehan, and K. Tanaka

Copyright © 2013 Carlos Zamarrón 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

Clear cell renal cell carcinoma (CCRCC) is the most common origin for metastasis in the thyroid. A 51-year-old woman was referred to our hospital for a subcarinal lesion. Ten years before, the patient had undergone a nephrectomy for CCRCC. Whole-body fluorodeoxyglucose positron emission tomography revealed elevated values in the thyroid gland, while the mediastinum was normal. An endoscopic ultrasonography-guided fine-needle aspiration biopsy of the mediastinal mass was consistent with CCRCC, and this was confirmed after resection. The thyroidectomy specimen also revealed lymphocytic thyroiditis, nodular hyperplasia, one follicular adenoma, two papillary microcarcinomas, and six foci of metastatic CCRCC involving both thyroid lobes. Curiously two of the six metastatic foci were located inside two adenomatoid nodules (tumor-in-tumor). The metastatic cells were positive for cytokeratins, CD10, epidermal growth factor receptor, and vascular endothelial growth factor receptor 2. No BRAF gene mutations were found in any of the primary and metastatic lesions. The patient was treated with sunitinib and finally died due to CCRCC distant metastases 6 years after the thyroidectomy. In CCRCC patients, a particularly prolonged survival rate may be achieved with the appropriate therapy, in contrast to the ominous prognosis typically found in patients with thyroid metastases from other origins.