If you feel a nodule in your thyroid gland, further examination is necessary. Blood samples will be taken to test thyroid function (FT4 and TSH), and an ultrasound of your thyroid gland and your throat will be performed. The amount of calcitonin and CEA (carcinoembryonic antigen) in your blood may also be measured. In benign nodules, these values are not elevated. In malignant nodules (medullary thyroid cancer), they are elevated.
The thyroid gland and the lymph glands can be clearly seen on an ultrasound. You can see the structure of the thyroid gland, how large it is and whether you have a nodule. The nodule will also be thoroughly examined: how large it is, where it is (in the thyroid gland or outside of it), and how it looks (containing clear fluid, like in a cyst, or specks of calcium).
To determine whether the cells in the nodule are benign or malignant, some tissue is taken by means of a needle biopsy. In order to do this, the nodule must be large enough to prick with a needle, at least one centimeter. A thin needle is used to prick the thyroid gland; the needle's path is monitored via ultrasound. Using ultrasound, the needle can be guided in such a way that the tip of the needle is directed precisely into the nodule. Then, a small piece of tissue is sucked out of the nodule and is later examined in the laboratory. This examination takes approximately ten days; in other words, you do not get the results immediately. During the needle biopsy procedure, you must remain motionless. To lessen the sensation of the needle prick, an anesthetic cream is applied. The result of a needle biopsy is not always clear-cut. If there is some doubt about the nature of the nodule, surgery may be required. During the operation, the half of the thyroid gland that contains the nodule is removed. This tissue can then be examined further in the laboratory.