Medullary cell carcinoma of the thyroid: metastases to the central nervous system.

We document a case of a patient who had been treated for a medullary cell carcinoma of the thyroid three years previously and who presented with a three month history of ataxia, weakness and headache. A CT scan showed contrast enhancing lesions in the posterior fossa. An MIBG uptake scan showed that there was some uptake in the cerebellar lesions; however, it was not sufficient to rely on this alone for treatment. The larger of these lesions was therefore surgically resected. Immunocytochemistry, using CAM 5.2, CEA and chromogranin, demonstrated a positive reaction which strongly favoured a diagnosis of metastases from a medullary cell carcinoma of the thyroid. However, absolute confirmation of the diagnosis was obtained using immunocytochemistry with calcitonin. Medullary cell carcinomas of the thyroid usually spread locally and metastasis to the brain has never before been reported.