Solitary cranial metastasis of thyroid carcinoma 13 years after primary surgery: Report of a case

Thyroid cancers rarely metastasize to the brain: the incidence of brain metastasis of differential thyroid carcinomas has been reported at only 0.69%–1.3%. We report a case of a solitary brain metastasis from thyroid follicular carcinoma found 13 years after primary surgery. A 73-year-old woman was admitted to our hospital for investigation of headaches, double vision, and facial nerve palsy, 13 years after a subtotal thyroidectomy for thyroid follicular carcinoma. Magnetic resonance imaging (MRI) showed a solitary mass in the midbrain associated with a focal osteolytic lesion of the temporal bone. Further radiological examinations revealed no other mass lesion. After making a provisional preoperative diagnosis of a primary brain tumor, we performed subtotal removal of the tumor. Histopathological examination confirmed metastasis of thyroid follicular carcinoma. Thus, the patient underwent completion thyroidectomy followed by internal radiotherapy. She has remained well in the 4 years since her operation, without any signs of further recurrence.