[Unusual metastasis of differentiated thyroid carcinoma]

Distant metastases of differentiated thyroid cancer are usually localised in the lung and bone; less common sites of metastases are the brain, liver, and skin. To find it in other sites it is exceptional. This work shows the clinical, histological and therapeutical characteristic of primary tumour in three cases of non-typical distant metastases of differentiated thyroid cancer. Follicular thyroid carcinoma was displayed in two cases, the first presented one metastases in right adrenal gland and the second in left kidney. Both cases were initially treated only with hemithyroidectomy, without posterior radioiodine. In one case, elevated serum thyroglobulin did not receive radioiodine treatment because Whole-Body Scintigraphy was negative. The thirst case was a papillary thyroid carcinoma treated with total thyroidectomy, ablative radioiodine and suppressor therapy with levothyroxine. However, posterior evolution was unfavourable and tumour presented metastases in common and less common sites like choroid. Histological study showed tall cell variant of papillary thyroid carcinoma. In summary, when the initial treatment of well-differentiated thyroid carcinoma it is inaccurate, it is possible to find common and less common sites metastases. Some variants of papillary thyroid carcinoma, like tall cell, have a worse prognosis and they can present metastases in less common sites.