A woman aged 52 was treated with radioactive iodine for a papillary carcinoma of the thyroid. Four years later she developed signs and symptoms of an intracranial space occupying lesion. A computed tomographic scan showed a mass in the right posterior frontal region. Although she was suspected of having metastatic disease a definite diagnosis was not established until she died 6 months later when post-mortem examination confirmed that she had a cerebral metastasis from a papillary carcinoma of the thyroid. There was no evidence of metastatic disease elsewhere in the body. Cerebral metastases from papillary carcinoma of the thyroid are uncommon but may occur in patients who have metastases in bones or lungs. A search of the literature has revealed only two patients with solitary cerebral metastases.