Thyroid Nodules

Sometimes, abnormal growths of cells, or nodules, occur on the thyroid. While most thyroid nodules are benign, a small portion of them — approximately 5 to 10 percent — are malignant and need to be removed.

Also See Thyroid Disorder Care

What Is a Thyroid Nodule?

A thyroid nodule is a lump or growth that forms within the thyroid gland. A growth on the thyroid gland can be:

  • Hot (producing thyroid hormones)
  • Cold (not making thyroid hormones)
  • Filled with fluid (cyst)
  • A single nodule or several
  • Benign (not cancer) or malignant (cancer)

Thyroid nodules are common – 50 percent of people will have at least one thyroid nodule by the age of 60.


Most thyroid nodules have no symptoms. They are often first detected during a routine physical exam. Some symptoms include:

  • Lump in the neck
  • Abnormal thyroid function test results
  • Difficulty swallowing
  • Pain in the neck
  • Tickle in the throat
  • Hoarseness or change in voice (not common, usually associated with thyroid cancer)

If your nodule is hot, or producing hormones, you may experience symptoms of an overactive thyroid gland (hyperthyroidism).

Risk Factors

Factors that may raise your risk for a thyroid nodule:

  • Thyroiditis
  • Thyroid cyst
  • Iodine deficiency
  • Thyroid cancer
  • Goiter
  • Family history of thyroid nodules, goiters, and thyroid cancer
  • History of radiation treatment to head and neck
  • Ionizing radiation exposure (especially in childhood)

Why Choose UC San Diego Health?

  • Our endocrinologists have Endocrine Certification in Neck Ultrasonography (ECNU) from the American College of Endocrinology (ACE), an advanced professional certification for physicians who perform consultations and diagnostic evaluations of thyroid and parathyroid disorders.
  • We can more accurately predict the likelihood that a thyroid nodule is cancerous or benign with genetic testing.
  • We are able to perform blood work and ultrasounds in the same visit, which means fewer appointments for patients.
  • Our thyroid specialists are regularly involved with multidisciplinary conferences that are shaping the future of thyroid disease care.
  • Our head and neck cancer experts use the most advanced therapies in the diagnosis and treatment of thyroid cancer, including minimally invasive surgery and immunotherapy.
  • UC San Diego Health endocrinologists are professionally certified in ultrasound-guided fine needle aspiration (FNA) for diagnosing thyroid nodules.

Thyroid Nodule Diagnosis

To properly evaluate a thyroid nodule and determine if it is cancerous, one or several tests may need to be done. These include:

  • Blood tests: Helps determine if the thyroid nodule is hyperfunctioning, or a "nodule." Blood tests measure levels of thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4).
  • Radioactive iodine scan: A nuclear medicine test that involves swallowing a small amount of radioactive iodine. Thyroid tissue is the only thing that takes up iodine. Once absorbed, a special camera is used to look for radioactivity.
  • Thyroid ultrasound: An ultrasound can help determine if a thyroid nodule is solid or filled with fluid. A solid nodule is more likely to be cancerous.
  • Fine needle aspiration (FNA): The best way to diagnose a thyroid nodule, an FNA involves removing a small number of cells from the thyroid nodule with an extremely fine needle.

Is it cancerous?

​Learn how we diagnose and treat cancerous thyroid nodules at UC San Diego Health.

Thyroid Cancer Program