title: Thyroid metastasis as initial presentation of clear cell renal carcinoma.
abstract: BACKGROUND
  Metastatic tumors account for 1.4-2.5% of thyroid malignancies. About 25-30% of patients with clear cell renal carcinoma (CCRC) have distant metastasis at the time of diagnosis, being the thyroid gland a rare localization [5%].
  
  
  METHODS
  A 62-year woman who underwent a cervical ultrasonography and a PAAF biopsy reporting atypical follicular proliferation with a few intranuclear vacuoles "suggestive" of thyroid papillary cancer in the context of a multinodular goiter was reported. A total thyroidectomy was performed and the histology of a clear cell renal carcinoma (CCRC) was described in four nodules of the thyroid gland. A CT scan was performed and a renal giant right tumor was found. The patient underwent an eventful radical right nephrectomy and the diagnosis of CCRC was confirmed.
  
  
  CONCLUSIONS
  Thyroid metastasis (TM) from CCRC are usually apparent in a metachronic context during the follow-up of a treated primary (even many years after) but may sometimes be present at the same time than the primary renal tumor. Our case is exceptional because the TM was the first evidence of the CCRC, which was subsequently diagnosed and treated.
  
  
  CONCLUSIONS
  The possibility of finding of an incidental metastatic tumor in the thyroid gland from a previous unknown and non-diganosed primary (as CCRC in our case was) is rare and account only for less than 1% of malignancies. Nonetheless, the thyroid gland is a frequent site of metastasis and the presence of "de novo" thyroid nodules in oncologic patients must be always considered and studied.
authors.affiliation: General and Digestive Surgery Service, Hospital Quirón Málaga, Avenida Imperio Argentina, n°1, Málaga CP 29004, Spain. Electronic address: cprptot@gmail.com.
authors.forename: César Pablo
authors.initials: CP
authors.lastname: Ramírez-Plaza
authors.affiliation: Endocrinology Service, Hospital Regional Málaga Carlos Haya, Avenida Carlos Haya s/n, Málaga CP 29010, Spain.
authors.forename: Marta Elena
authors.initials: ME
authors.lastname: Domínguez-López
authors.affiliation: Urology Service, Hospital Regional Málaga Carlos Haya, Avenida Carlos Haya s/n, Málaga CP 29010, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Blanco-Reina
keywords: Carcinoma; Metastasis; Renal; Thyroid; Treatment
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