The thyroid gland is a butterfly-shaped gland located in the low anterior neck. It produces thyroid hormone, which helps to regulate the body’s metabolism. The functional capacity of the thyroid is measured by blood tests. Excessive production of thyroid hormone (hyperthyroidism) can cause palpitations, tremors, weight loss, and heat intolerance. Conversely, an under-active thyroid gland (hypothyroidism) can result in fatigue, weight gain, and cold intolerance.
A thyroid nodule is a growth in the thyroid gland. Thyroid nodules are extremely common, and may be solitary or multiple (multinodular goiter). It is estimated that approximately 5-10% of the population has a palpable thyroid nodule, and between 30-85% have tiny thyroid nodules that are too small to palpate.
In most people with thyroid nodules, the gland produces a normal level of thyroid hormone (euthyroid state). Statistically, approximately 5-10% of nodules are cancerous. Some patients have findings that increase the risk of malignancy. A history of exposure to radiation to the neck is such a risk factor, as is a family history of thyroid cancer. Hoarseness, lymph node enlargement, and fixation of the nodule can also increase the risk of malignancy. Fortunately, the vast majority of thyroid cancers are treatable and carry an excellent prognosis.
Most thyroid nodules do not require surgery. The primary indications for thyroidectomy are suspicion of cancer, large size, substernal location (nodules that grow inferiorly into the chest), or symptoms (throat pressure, difficulty swallowing, respiratory distress, or cosmetic disfigurement from a visible goiter). Over-functioning nodules are sometimes best treated by surgery, as well.
The most important tests to evaluate a thyroid nodule are Ultrasound of your thyroid (shows size, location and characteristics of the nodule), a TSH level (a blood test that evaluates the function of the gland) and a fine needle aspiration (FNA) biopsy to evaluate the nodule for malignancy. Although FNA is highly accurate, it is not 100% accurate in making a diagnosis. FNA is usually performed by Radiologists under ultrasound guidance. There are some types of thyroid nodules (follicular tumors) where FNA cannot distinguish benign from malignant nodules- these nodules are usually best managed by thyroidectomy.
Please refer to Thyroid Surgery for more information on the procedure.