Solitary brain metastases from thyroid carcinoma: study of 6 cases.

AIMS AND BACKGROUND: Although systemic metastases from thyroid cancer are relatively frequent, they rarely affect the nervous system and only exceptionally originate from well-differentiated carcinoma. METHODS: The authors describe 6 cases of solitary brain metastases from thyroid carcinoma, well-differentiated in 3 cases and anaplastic in the other 3 cases. RESULTS: Four patients were females and 2 males (M:F ratio, 1:2); average age was 51 yrs (range 48-56). On average, the interval between diagnosis of the thyroid tumor and appearance of the metastasis was 2.8 years (range 1-12 years) and was shorter in the anaplastic forms (1.2 versus 4.4 years). Average survival was 15 months (range 6-48 months); in particular, average survival was longer in patients with well-differentiated carcinoma (9 vs 21 months) as also in those who did not present other metastatic sites (6 vs 24 months). Death was due to systemic progression of the disease in 4 cases and to brain-relapse in the other 2 cases. CONCLUSIONS: Surgery, radioactive iodine (where uptake is demonstrable), and radiotherapy are the main therapies available for metastases from thyroid carcinoma. However, survival of patients appears to be modified by the type of treatment performed.