Medullary carcinoma of the thyroid masquerading as idiopathic vocal cord paralysis

The following conclusions may be drawn as a result of our study: 1. Serum calcitonin by radioimmunoassay proved to be the only valid preoperative indicator in a case of medullary carcinoma of the thyroid occurring with vocal cord paralysis. This test should be considered in all cases of idiopathic recurrent laryngeal nerve paralysis, especially when obscure thyroid pathology is suspected. 2. Provocative calcitonin testing, such as a calcium infusion test, may help verify presence or absence of disease in equivocal cases of calcitonin assay. 3. Vocal cord paralysis may be the first sign of intrathroid malignancy. 4. In the furture, serum calcitonin assay (drawn posttreatment) may be a valuable prognostic indicator and may guide the need for additional treatment.