title: Metastasis from renal cell carcinoma to thyroid presenting as rapidly growing neck mass.
abstract: BACKGROUND
  Renal cell carcinoma (RCC) is commonly known as the "internist's tumor" because of its unpredictable behavior. Metastasis to the thyroid gland is rarely found in clinical practice.
  
  
  METHODS
  We report a rare case of non-thyroid malignancies NTM from renal cell carcinoma 1.5 years after radical nephrectomy in a 58-year-old man with a rapidly growing neck mass.
  
  
  CONCLUSIONS
  Malignant melanoma, breast carcinoma, lung, and skin cancer are the most common sources of non-thyroid malignancies (NTM). Although metastases of NTMs to the thyroid gland are uncommon in clinical practice, it should be considered in patients with a history of prior malignancy and a new thyroid mass.
  
  
  CONCLUSIONS
  Isolated thyroid metastasis should be considered in patients with a previous history of cancer and newly developing thyroid mass.
authors.affiliation: Radiology Department, Urmia University of Medical Sciences, Urmia, West-Azerbaijan, Iran. Electronic address: afshin.mohdi@gmail.com.
authors.forename: Afshin
authors.initials: A
authors.lastname: Mohammadi
authors.affiliation: Student Research Committee, Urmia University of Medical Sciences, Urmia, West-Azerbaijan, Iran.
authors.forename: Seyed Babak Mosavi
authors.initials: SB
authors.lastname: Toomatari
authors.affiliation: Division of Interventional Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, 290 GRB, Boston, MA 02114, USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ghasemi-Rad
keywords: Metastasis; Renal cell carcinoma; Thyroid