Thyroid cancer could have a familial susceptibility and may occur as hereditary syndromes or as isolated tumor. They classified as medullary and non-medullary thyroid cancer according to the histological origin since the tumor behavior,clinical characteristics, etiology and genetics are very different. Approximately 25% of medullary thyroid cancer are hereditary when in non-medullary thyroid cancer the reported prevalence varies from 2.5 to 11%. Even though the familial thyroid cancer is rare, it is essential to detect these patients. Detection would let us study the patient‘s relatives and be able to do an early diagnose on them. This could allow to prevent cancer development and treatment before metastasis occur.