CT scanning as an adjunct to screening for medullary carcinoma of the thyroid.

CT scanning of the thyroid following oral administration of potassium iodate was performed on two sisters in whom raised calcitonin levels had been found at a pentagastrin stimulation test undertaken to screen for medullary carcinoma of the thyroid. Three histologically proven, clinically occult C-cell carcinomas measuring 2 mm or less were detected by CT scanning. This technique may be useful prior to surgery in patients in whom medullary carcinoma of the thyroid is suspected but not proven.