Medullary Thyroid Carcinoma
In 1951 Horn described and illustrated what is now known as medullary thyroid carcinoma (MTC). A few years later, Hazard and colleagues reported 21 cases of “this medullary or solid form of thyroid carcinoma” and recommended that it be recognized as a distinct clinicopathologic entity. In 1966, Williams suggested that it was derived from the calcitonin-producing “C cells” or parafollicular cells of the thyroid. A few years later, investigators showed conclusively that MTCs were immunoreactive for calcitonin.
MTC comprises approximately 7% of thyroid carcinomas. It occurs in sporadic (in 85% of cases) and heritable forms. The heritable forms include multiple endocrine neoplasia (MEN) type 2A (Sipple’s syndrome), which includes pheochromocytomas and hyperparathyroidism in some families; MEN type 2B (mucosal neuroma syndrome or Gorlin’s syndrome), which consistently includes mucosal neuromas and somatic marfanoid habitus; and familial medullary thyroid carcinoma (FMTC). The hereditary forms are characterized by an autosomal dominant mode of inheritance and are associated with point mutations in the RET proto-oncogene on chromosome 10.
KeywordsPapillary Carcinoma Medullary Thyroid Carcinoma Autosomal Dominant Mode Familial Medullary Thyroid Carcinoma Parafollicular Cell
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