Definition
A thyroid nodule is a growth (lump) in the thyroid gland. The thyroid gland is located at the base of the neck.
Overview, Causes, & Risk Factors
Thyroid nodules are growths of cells in the thyroid gland. These growths can be noncancerous (benign) or cancerous (malignant). Some nodules are fluid-filled (cysts), while others are made of thyroid gland cells. Sometimes, what feels like one nodule will actually be a collection of small nodules.
Thyroid nodules are more common in women than in men. A person’s chance of a thyroid nodule increases with age.
Only a few thyroid nodules are cancerous. (See: Thyroid cancer)
The following characteristics increase the chances that a thyroid nodule is cancerous:
- A hard nodule
- A nodule that is stuck to nearby structures
- Family history of multiple endocrine neoplasia type II
- Family history of thyroid cancer, especially medullary thyroid carcinoma
- Hoarse voice due to vocal cord paralysis
- Age — younger than 20 years or older than 70
- History of radiation exposure to the head or neck
- Male gender
Causes of thyroid nodules are not always found, but can include:
- Hashimoto’s disease
- Iodine deficiency
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Thyroid nodule: Overview, Causes
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Thyroid nodule: Symptoms & Signs, Diagnosis & Tests
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Thyroid nodule: Treatment
Review Date : 4/29/2009 Reviewed By : David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Deborah Wexler, MD, Assistant Professor of Medicine, Harvard Medical School, Endocrinologist, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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