Thyroid nodule Health Article

Definition

A thyroid nodule is a growth (lump) in the thyroid gland. The thyroid gland is located at the base of the neck.

Alternative Names

Thyroid adenoma; Thyroid carcinoma; Thyroid incidentaloma

Causes, incidence, and risk factors

Thyroid nodules are growths of cells in the thyroid glands. These growths can be benign (non-cancerous) or malignant (cancerous). Some nodules are fluid-filled (cysts), while others are completely made of thyroid gland cells. Sometimes, what feels like one nodule will actually be a collection of small nodules close together.

Thyroid nodules that are big enough to feel during a physical exam occur in 5 - 7% of the population. Smaller nodules occur in as many as 50% of people aged 60 or older. Thyroid nodules are more common in women than in men. A person's chance of a thyroid nodule increases with age.

Only 4 - 5% of thyroid nodules are cancerous. (See: Thyroid cancer)

The following characteristics increase the risk for a cancerous nodule:

• Family history of medullary thyroid carcinoma
• Family history of multiple endocrine neoplasia Type II
• A hard nodule
• A nodule that is stuck to nearby structures
• Vocal cord paralysis

Other risk factors for a cancerous nodule include:

• Male gender
• Age -- younger than 20 years or older than 70
• History of radiation exposure to the head or neck

Causes of thyroid nodules are not always found, but can include:

• Iodine deficiency
• Suppression of thyroid hormone
• Hashimoto's disease

Symptoms

Most thyroid nodules produce no symptoms.

Large nodules can press against other structures in the neck. Symptoms may include:

• Difficulty breathing  
• Difficulty swallowing  
• Hoarseness or changing voice   
• Pain in the neck
• Goiter

Nodules that produce thyroid hormones will cause symptoms of hyperthyroidism, including:

• Weight loss 
• Increased appetite 
• Nervousness
• Restlessness 
• Clammy skin
• Skin blushing or flushing
• Bounding pulse

Thyroid nodules resulting from Hashimoto's disease may cause symptoms of hypothyroidism, including:

• Intolerance to cold
• Fatigue
• Dry skin
• Hair loss
• Unintentional weight gain
• Facial swelling