Medullary thyroid carcinoma (MTC), occurring sporadically or as an autosomal dominant trait, accounts for 5-10% of all thyroid gland neoplasms. While the sporadic variant originates from somatic rearranged-during-transfection (RET) mutations, the inherited variant is preceded by germ-line mutations of the RET proto-oncogene. Analysis of the transformations of this certain gene is the cornerstone of diagnostic and prognostic approaches in MTC. Additionally, a panel of histopathological evaluations, biochemical markers, and imaging procedures play a pivotal role in the management of MTC. The survival rate of MTC is relatively low compared to differentiated thyroid neoplasia and is highly influenced by the stage of tumors. Improvement in MTC surveillance significantly depends on early diagnosis as well as implementation of proper screening modalities in hereditary subtypes. The present review addresses medullary thyroid carcinoma, and in particular, the current diagnostic approaches to this challenging malignancy.