CALCA and medullary thyroid gland carcinoma: Medullary thyroid carcinoma (MTC) accounts for 4–10% of all thyroid cancer cases [1,2] and originates from the parafollicular cells of the thyroid or C-cells, physiologically responsible for the secretion of calcitonin; C-cell hyperplasia (CCH) is considered as the first stage of histological progression that evolves into MTC [3,4].