ABSTRACT
In 1959 Hazard and colleagues defined medullary thyroid carcinoma (MTC) as a separate disease with specific clinical and pathological features. They found that the tumor was characterized by solid nonfollicular growth pattern, presence of amyloid in the stroma, and high incidence of lymph node metastases [1]. Within the next 10 years MTC was recognized to originate from the parafollicular C cells, secrete calcitonin, and occur in both sporadic and hereditary forms (2-6).The disease has a wide clinical spectrum ranging from aggressive tumors to rather indolent disease. In contrast to other thyroid diseases, MTC occurs almost equally in both sexes (7). In a study from the National Cancer Registry in Sweden, the agestandardized annual incidence of all MTC, sporadic and hereditary, was 2.1 per million inhabitants during 19701980. During this period MTC constituted 5.2% of all reported thyroid carcinomas in Sweden. Sporadic MTC was rather evenly distributed in the country, which speaks against environmental factors as causative agents. Hereditary MTC was more confined to certain regions, reflecting the location of identified families and differences in screening activity. Population-based surveys in the United States and Canada showed that MTC constituted 410% of the thyroid carcinomas. Data from the Thyroid Cancer Registry in Japan showed 1.55% of MTC among the patients with thyroid malignancies registered from 1977 to 1980.
