A Case of Breast Cancer Metastasized to the Thyroid Gland

ABSTRACT

The thyroid gland has been widely considered an infrequent metastasis site despite the fact that the gland has a rich supply. However, the incidence of metastasis to the thyroid gland in autopsy series varies from 0.5% to 24.2%. In most autopsy series, breast and lung cancers have been the two most frequent metastatic diseases involving the thyroid gland. In contrast, renal cell carcinoma is usually the most frequent source of metastasis in clinical series. Metastatic disease involving the thyroid gland may be a diagnostic challenge and must be distinguished from primary thyroid tumors. It is usually acknowledged as a terminal event and the effectiveness of conventional treatment has been questioned. It is, however, possible that early diagnosis and aggressive management can contribute to prolonged survival in selected patients. We report here a case of breast cancer metastasized to the thyroid gland along with a review of the literatures.