Discussion in the diagnosis and treatment of medullary thyroid cancer        CHEN Xi. Department of Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine，Shanghai 200025，China
Abstract    Medullary thyroid cancer (MTC) originates from parafollicular C cells of the thyroid gland, and accounts for about 4% of thyroid cancer cases. MTC presents as part of an autosomal dominant inherited disorder related to multiple endocrine tumor type 2 (MEN-2) in about 20%～25% of cases, including MEN-2a, MEN-2b and family MTC, and as a sporadic tumor in the remainder. Calcitonin is a specific tumor marker of MTC, which indicates the tumor onset, residue and recurrence. Calcitonin doubling-time is related to the prognosis. The only possible to cure MTC is total thyroidectomy and lymph node dissection, and the prophylactic surgery benefits the MEN-2 related patients.