Breast cancer metastatic to the bilateral thyroid: a case report and literature review

The thyroid gland is a relatively rare site for secondary malignancy. Here we describe the case of a 41-year-old woman with a history of bilateral breast cancer. She presented with elevated serum carbohydrate antigen 153 level. Ultrasonography revealed the bilateral thyroid lobes and isthmus diffuse distribution of point-like calcifications. No nodules were palpable, and total thyroidectomy was performed. A firm diagnosis of metastatic breast carcinoma to the bilateral thyroid was established. With this report, we could strengthen the argument that any patient with a thyroid lesion and a history of malignancy should be considered to have a metastasis until proven otherwise; further, we conclude that total thyroidectomy for the multifocality of metastases to the thyroid gland is feasible when metastatic cancer is limited to the thyroid. With a combination of comprehensive treatments, such as chemotherapy, radiotherapy and endocrine therapy, the survival of the patient can be prolonged.