Management of individual tumor syndromes. Medullary thyroid carcinoma and hyperparathyroidism.

Significant advances have been made in the understanding of the pathophysiology and the ability to effectively screen for and treat medullary thyroid carcinoma. The parafollicular cells, or C-cells, are the cell of origin for medullary thyroid carcinoma. C-cell hyperplasia is a premalignant disease that progresses rapidly to medullary thyroid carcinoma. C-cells produce calcitonin, which serves as a marker to prospectively screen patients for C-cell disease. One major concern in screening for this disease has been the incidence of false positive results. This problem is addressed in light of new, more stringent criteria for the diagnosis of C-cell hyperplasia. The association of hyperparathyroidism with MEN 2 is discussed with evidence that thyroidectomy of C-cell disease may affect the incidence of parathyroid disease.