ABSTRACT

A 57-year-old woman was admitted with a left breast mass. Metastatic follicular thyroid carcinoma (FTC) was diagnosed two years previously with excision of a parietal bone lesion. Two sessions of radioactive I-131 were administered after total thyroidectomy due to multiple metastases in the lungs and bones. A regimen of single agent adriamycin was given when the disease progressed. Partial remission was obtained after 6 cycles of chemotherapy. After five months following chemotherapy she was admitted with a left breast mass. Surgical excision revealed FTC metastasis. The patient has a stable disease twelve months after metastasectomy. Metastasis of thyroid cancer to the breast is a very rare occurrence. Only a few cases were reported. It is important to distinguish metastatic malignancies from primary breast tumors to avoid destructive surgery and maintain the appropriate treatment of the primary tumor.