The term thyroid nodule refers to an abnormal overgrowth of cells in the thyroid gland, which causes a lump in the thyroid. The majority of thyroid nodules are benign (>90%). By age 60, about half the population has at least one thyroid nodule. The thyroid is a butterfly-shaped gland that is located centrally in the neck, just above the collarbones and below the larynx (voicebox).
The main function of the thyroid is to regulate the body’s metabolism through production of thyroid hormones, T4 and T3.
Symptoms & Signs
Most thyroid nodules do not cause symptoms or signs. Most are discovered incidentally on routine imaging tests done for other reasons, such as Ultrasounds or CT scans.
It may also be noticed on routine physical examination by your doctor as a lump in your neck. Some patients may notice a lump in their own neck, and seek medical attention.
Uncommonly, thyroid nodules can overproduce thyroid hormone, and cause symptoms/ signs of an overactive thyroid (HYPERthyroidism). See Hyperthyroidism info.
Thyroid function tests, and often thyroid antibody levels, will be checked to evaluate overall thyroid function.
Ultrasound of the thyroid will be performed to further evaluate the size/ shape and internal characteristics of the nodules, as well as to check the rest of the neck for lymph nodes or other lumps.
Nuclear medicine thyroid scan may be requested to assess whether the thyroid nodule is functioning normally/ overfunctioning or “cold” (non-functioning).
In certain cases, Fine needle Aspiration Biopsy may be required. This is usually done under ultrasound guidance and involves insertion of a needle into the thyroid nodule, and aspiration of cells from the nodule. These cells are then examined microscopically by a pathologist to detect any cells which may be suspicious for the presence of thyroid cancer.