Medullary carcinoma of the thyroid: differentiating the types and current management.

Medullary Ca of the thyroid (MCT) occurs in sporadic and familial form. When familial MCT is associated with pheochromocytoma and parathyroid adenoma or hyperplasia it is called multiple endocrine syndrome type IIa (MEN type IIa). When the syndrome is associated with mucosal neuromata or marfanoid habitus it is called MEN type IIb or type III. When familial MCT is not associated with the above tumors, it is called type IV. Measurement of serum calcitonin is the diagnostic method of choice. CEA is a better prognostic marker than calcitonin. When MCT is confined to the thyroid, total thyroidectomy is recommended. If lymph nodes are involved, lymph node neck dissection is required. I131 therapy and radiotherapy are ineffective. Optimal chemotherapy has not yet been established.