[Thyroid metastases]

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.

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).

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.

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.