Abstract

Different mutations of RET proto-oncogenes serve as the basis for three types of clinical manifestations of MEN2 syndrome: familial medullary thyroid carcinoma, MEN2A and MEN2B syndromes. All these subtypes are characterized by medullary thyroid carcinoma. Calcitonin is a significant tumour marker for medullary thyroid carcinoma the sensitivity of which is enhanced with the use of calcium stimulation test. Medullary thyroid carcinoma could be prevented with timely thyroidectomy among the carriers of asymptomatic germline RET proto-oncogene mutation. The article presents the report of a case where the slow but consistent rise in calcitonin conceales a medullary thyroid carcinoma caused by RET proto-oncogene mutation. The patient’s father and sister were both genetically tested positive for the same gene mutation. Genetic tests for medullary thyroid carcinoma are always indicated to ensure the further surveillance strategy for the patient and his or herfamily members.