Skull Base Metastasis From Follicular Thyroid Carcinoma

—Two Case Reports—

Abstract

A 58-year-old woman and a 71-year-old woman presented with extremely rare skull base metastases from follicular thyroid carcinoma (FTC). Surgical removal and external radiotherapy were performed followed by iodine-131 (¹³¹I) brachytherapy and thyroid hormone administration. The metastatic tumors in the skull base were well controlled. Treatment for skull base metastasis from FTC includes surgical debulking of the metastatic lesion, as well as complete resection of the thyroid gland, followed by internal irradiation with ¹³¹I, external irradiation, and administration of thyroid hormone to prevent tumor growth by suppression of endogenous thyroid-stimulating hormone. Skull base metastases may be the initial clinical presentation of FTC, with silent primary sites. The possibility of skull base metastasis from FTC should be considered in patients with clinical symptoms of cranial nerve dysfunction and radiological findings of bone destruction.