The correct answer is B. The first test for a thyroid nodule is the thyroid-stimulating hormone test; if normal, the most appropriate next step is fine-needle aspiration which can be done safely and without complication. An ultrasound can be used to differentiate between solid and cystic structure and can be used to guide the needle aspiration. The fine-needle biopsy provides a definitive diagnosis in most cases and is the most helpful test in guiding management.
CT scanning of the thyroid gland (choice A) is important in the workup of a patient who has a goiter and is complaining of obstructive symptoms such as shortness of breath or difficulty swallowing. It has no role in the initial workup of a thyroid nodule. If the patient has thyroid cancer, the CT scan of the thyroid can be used to help stage the cancer.
Serial physical examinations (choice C) are not acceptable management. Thyroid cancer is curable in its early stages, so efforts should be made to rule out carcinoma in these patients.
Thyroid uptake scanning (choice D) may be useful; however, a fine-needle aspiration is generally considered the next best step in this case. Approximately 20% of nonfunctioning thyroid nodules (cold appearance) prove to be malignant; functioning nodules (hot nodules) are seldom malignant. The thyroid uptake scanning provides a percentage number (high or low) that demonstrates the activity of the gland and is used to differentiate between Graves disease (high uptake), multinodular goiter (patchy uptake) and subacute thyroiditis (low uptake).
PEARL: A patient who has a thyroid nodule should have a full thyroid function evaluation performed. The first test performed should be the TSH; a suppressed level suggests hyperthyroidism and a hot nodule, which lessens the possibility for cancer. The next test should be a fine-needle biopsy (if the TSH is not suppressed). Histology will identify whether the patient has cancer and also will identify the type of cancer that the patient has. A thyroid scan can help to identify the nodule and whether it is hyper- or hypofunctioning.
