What Are Thyroid Nodules?

The thyroid is a gland at the base of the neck which makes a hormone responsible for regulating metabolism. Thyroid nodules are solid or fluid-filled growths that occur in the thyroid. Most thyroid nodules are not cancerous and are inactive. Some thyroid nodules may become large enough to be felt or cause symptoms due to their size.

Thyroid nodules are very common in the adult population and become more common with age. Approximately half of the U.S. population has thyroid nodules at retirement age. Approximately five percent of thyroid nodules are cancerous. For the majority of patients, there is no particular cause for their thyroid nodule.

Thyroid nodules are often detected during routine physical examinations or imaging tests taken for other reasons. Typically, the first steps to evaluate a thyroid nodule are to determine how well the thyroid functions by performing blood tests and to determine the exact size and appearance of the thyroid nodule by evaluating the thyroid with an ultrasound.

The best test to evaluate a thyroid nodule for cancer is a fine-needle aspiration biopsy (FNA), which is a simple procedure that is done by physicians in the Northwestern Medicine Comprehensive Thyroid and Endocrine Surgery Program. Our physicians perform a comprehensive evaluation of risk factors for thyroid cancer, determine the appearance and function of the thyroid, and then select nodules that should be biopsied. Nodules are selected for biopsy based on the risk that they may be cancerous. It takes several days to get results of thyroid FNA biopsies.

Following an FNA biopsy, our physicians will provide a strategy for treating the thyroid nodules. Benign nodules are usually observed over time with ultrasound exams. Suspicious nodules may be evaluated by additional tests such as molecular diagnostics. Surgery is recommended for nodules determined to be malignant or to have a high risk of malignancy.

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    Related Resources

    Thyroid Ultrasound Brochure: Learn about the preparations and care needed before and after this procedure. English | Spanish