[Medullary thyroid carcinoma and multiple endocrine neoplasia type 2].

Medullary thyroid carcinoma (MTC) is a rare malignancy and compromises only 3 % of all thyroid carcinomas. MTC cells secret calcitonin, which serves as a sensitive tumor marker for screening and follow-up of MTC. Calcitonin screening in patients with nodular goiter allows for early diagnosis of MTC and surgical curative treatment. In 25 % of patients MTC occurs as an integral part of multiple endocrine neoplasia type 2 (MEN2), an autosomal dominant inherited tumor syndrome. It is caused by germline mutations in the RET protooncogene. In gene carriers early diagnosis and treatment through prophylactic thyroidectomy is possible. MTC is a slowly growing tumor with a good prognosis and 5 and 10 year survival rates up to 80 and 60 %. In the follow-up a dynamic risk stratification allows for a personalized disease management. In symptomatic and progressive metastasizing MTC tyrosine kinase inhibitors are an effective therapy.