Thyroid nodules are common...
Thyroid nodules are common. Clinically apparent nodules (ones your doctor can feel on examination of your neck) can be found in 4 % of adults.
Thyroid nodules are more common in women: 6.4 % women, 1.5 % men.
20% of women have nodules that can be seen on a thyroid ultrasound.
50% of women older than age 50 have nodules that can be seen on a thryoid ultrasound. The incidence of thyroid nodules goes up with age.
What kind of conditions cause nodules in the thyroid?
Only 5 - 6.5 % of thyroid nodules are cancer. Therefore most nodules are benign. There are many things that can cause a nodule in the thyroid:
| Benign Thyroid Nodules | Thyroid Cancer |
| Simple or Colloid Cyst | Papillary thyroid cancer |
| Follicular adenoma (benign tumor) | Follicular thyroid cancer |
| Thyroiditis (inflamed thyroid) | Medullary thryoid cancer |
| Parathyroid gland (adenoma, hyperplasia) | Anaplastic thyroid cancer |
| Thyroid Lymphoma | |
| Metastasis (cancer spread to thyroid from elsewhere in the body) |
Risk of Cancer
The risk of a thyroid nodule being cancer is influenced by several factors:
| Age | Age < 30 or > 60 increases risk, Children are at 2x higher risk |
| Sex | Male are at 2x higher risk |
| Radiation Exposure to Head/Neck for treatment (acne, tonsils, enlarged thymus, Hodgkin's, etc.), radiation spill (Chernobyl) | Nodules occur in 20-27% of exposed
Papillary cancer occurs in 30-33% of these nodules |