Thyroid Nodules
Lumps in the thyroid gland, usually harmless but sometimes needing evaluation
Quick Facts
- Type: Endocrine (thyroid) condition
- Most are: Benign (noncancerous)
- Often: Found by chance, with no symptoms
- Key test: Ultrasound, sometimes a needle biopsy
Overview
Thyroid nodules are growths or lumps that develop in the thyroid, a butterfly-shaped gland at the front of the neck that makes hormones controlling metabolism. Nodules are very common and become more frequent with age. They may be solid, fluid-filled (cysts), or a mix.
The large majority of thyroid nodules are benign (not cancer) and cause no problems. Most are discovered by chance during a physical exam or an imaging test done for another reason. The main goals of evaluation are to check whether a nodule is producing too much thyroid hormone and to make sure it is not cancerous, since a small share of nodules are.
Symptoms
Most thyroid nodules cause no symptoms. When they do, signs may include:
- A lump that can be felt or seen in the neck
- A feeling of fullness or pressure in the throat
- Difficulty swallowing or, rarely, breathing if a nodule is large
- Hoarseness
If a nodule produces excess thyroid hormone, symptoms of an overactive thyroid can occur, such as a fast heartbeat, weight loss, nervousness, tremor, and feeling hot. A sudden increase in size or pain may occur if a nodule bleeds.
Causes
Thyroid nodules can develop for several reasons:
- Overgrowth of normal thyroid tissue, the most common type, usually benign
- Thyroid cysts, fluid-filled lumps that are usually benign
- Chronic thyroid inflammation, such as Hashimoto's thyroiditis, which can cause nodules and an enlarged gland
- Multinodular goiter, an enlarged thyroid with multiple nodules
- Overactive ("hot") nodules that make excess hormone
- Thyroid cancer, which accounts for a small minority of nodules
Iodine deficiency can contribute to nodule and goiter formation in some regions.
Risk Factors
- Older age
- Female sex
- A family history of thyroid nodules or thyroid cancer
- Past radiation exposure to the head or neck
- Iodine deficiency
- Existing thyroid conditions such as Hashimoto's thyroiditis
Diagnosis
Evaluation aims to assess thyroid function and the nature of the nodule:
- Blood tests measuring thyroid hormone levels (including TSH) to check whether the gland is working normally.
- Thyroid ultrasound, the key imaging test, which shows a nodule's size, whether it is solid or fluid-filled, and features that suggest higher or lower risk.
- Fine-needle aspiration biopsy, in which a thin needle samples cells from a suspicious nodule for examination, often guided by ultrasound.
- Radioactive iodine scan in selected cases, especially when a nodule may be overactive.
Treatment
Treatment depends on the type of nodule, biopsy results, and whether it affects hormone levels:
- Watchful waiting: Most benign nodules need no treatment and are simply monitored with periodic ultrasound.
- Treating overactive nodules: A hormone-producing nodule may be treated with anti-thyroid medication, radioactive iodine, or surgery.
- Surgery: Recommended if a nodule is cancerous, suspicious, very large, or causing pressure symptoms.
- Cyst drainage: A fluid-filled nodule causing symptoms can sometimes be drained.
- Thyroid cancer treatment: Usually involves surgery and may include radioactive iodine and hormone therapy afterward.
Prevention
Most thyroid nodules cannot be prevented, but some general measures may help:
- Ensure adequate dietary iodine, for example from iodized salt where deficiency is a concern
- Discuss any history of head or neck radiation with your doctor
- Attend recommended follow-up if you have known nodules or thyroid disease
- Report any new neck lump, swallowing difficulty, or voice change
When to See a Doctor
See a doctor if you notice a lump in your neck, trouble swallowing, persistent hoarseness, or symptoms of an overactive thyroid such as a racing heart and unexplained weight loss. Seek prompt care for:
- A rapidly growing neck lump
- Difficulty breathing
- A lump that is hard, fixed, or associated with swollen neck glands
Most nodules are harmless, but these features warrant timely evaluation.
Frequently Asked Questions
Are thyroid nodules usually cancer?
No. The large majority of thyroid nodules are benign and harmless. Only a small minority turn out to be cancer, which is why evaluation with ultrasound and, when needed, a needle biopsy is used to identify the few that require treatment.
How are thyroid nodules checked for cancer?
Doctors use a thyroid ultrasound to look at a nodule's features and a fine-needle aspiration biopsy to sample cells from suspicious nodules. Blood tests also assess whether the thyroid is overactive. Together these guide whether treatment is needed.
Do thyroid nodules need to be removed?
Most do not. Benign nodules that cause no symptoms are usually just monitored with periodic ultrasound. Surgery is considered when a nodule is cancerous or suspicious, very large, causing pressure symptoms, or producing excess hormone.
Can a thyroid nodule affect my hormones?
Yes. Some nodules produce extra thyroid hormone, causing an overactive thyroid with symptoms like a fast heartbeat, weight loss, and nervousness. Blood tests detect this, and such nodules may be treated with medication, radioactive iodine, or surgery.
When should I worry about a neck lump?
See a doctor for any new neck lump, especially one that grows quickly, is hard or fixed, or comes with trouble swallowing, voice changes, or swollen glands. Seek prompt care for any difficulty breathing.
References
- American Thyroid Association. Thyroid nodules.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
- Mayo Clinic. Thyroid nodules.
- MedlinePlus, U.S. National Library of Medicine. Thyroid nodules.