ABSTRACT
Medullary thyroid carcinoma (MTC) is a tumor of the parafollicular C cells of the thyroid. Normal C cells are located in the basal layers of thyroid follicles, account for about 1% of thyroid cells, and are typically associated with the production and secretion of calcitonin (CT), a calcium lowering hormone, whose secretion is retained also by the neoplastic C cells of MTC at higher rates compared to normal C cells.
