Medullary thyroid carcinoma

Abstract Medullary thyroid carcinoma (MTC) is a rare calcitonin-secreting tumour of the parafollicular or C cells of the thyroid. As the C cells originate from the embryonic neural crest, MTC often have the clinical and histological features of neuroendocrine tumours. They account for 8–12% of all thyroid carcinomas and occur in both sporadic and hereditary forms (1). The majority of patients have sporadic MTC (70%), while 30% have hereditary MTC. The sex ratio in sporadic MTC is 1:1.3 (male to female), while both sexes are nearly equally affected in the familial variety (2). The highest incidence of sporadic disease occurs in the fifth decade of life, while hereditary disease can be diagnosed earlier, depending on the possibility of genetic and biochemical screening.