Study aim: The aim of this retrospective study was to report a short series of thyroid metastases and to emphasize their unusual occurrence and their poor prognosis.
Patients and method: From January 1990 to December 1999, among 619 patients operated for a thyroid malignancy, 14 patients had a thyroid metastasis (2.2%). Mean age of the patients was 66 years (range: 35-81). The thyroid metastasis revealed the primitive tumor (n = 8) or occurred in the follow-up of a cancer already treated (n = 6). The primitive tumor was renal (n = 3), breast (n = 3), lung carcinoma (n = 4) and melanoma (n = 1). In the 3 other patients, the primitive tumor was not detected. The thyroid metastasis was apparently isolated in 13 patients. The surgical procedure was a total (n = 3) or partial (n = 7) thyroidectomy and a cervicotomy with biopsy (n = 4).
Results: Eleven patients died less than one year after the diagnosis of the metastasis. One patient survived 1 year, another 2 years. One patient only was alive 22 years after the diagnosis of his renal tumor and 10 years after total thyroidectomy.
Conclusion: Thyroid metastases are clinically very rare and much more frequent at post-mortem examination. They may reveal the primitive cancer but are often detected during the follow-up after treatment of the primitive tumor. When thyroid metastasis is isolated, a total thyroidectomy is justified especially in renal carcinoma, as long-term survivals have been reported.