Diagnosis of medullary thyroid cancer

Medullary thyroid cancer (MTC) accounts for 5-10% of all thyroid cancers. The majority of medullary thyroid cancers are sporadic, but 25% of cases are inherited as a result of germline mutations in the RET proto-oncogene. In sporadic cases MTC presents as a thyroid nodule discovered at palpation or at thyroid ultrasonography, and is indistinguishable from thyroid nodules of different histology. Since effective treatment of MTC is only possible when the tumour is limited to the thyroid gland, early discovery has a decisive impact on how radical initial surgical treatment needs to be. Recent data suggest that in sporadic cases, early discovery of thyroid nodular disease is possible when screening serum calcitonin measurement, while screening for germline RET proto-oncogene mutations is fundamental in first degree relatives of patients with hereditary MTC.