Thyroid nodules are solid or fluid-filled lumps that form within your thyroid, a small gland located at the base of your neck, just above your breastbone.
The great majority of thyroid nodules aren't serious and don't cause symptoms. Thyroid cancer accounts for only a small percentage of thyroid nodules.
You often won't know you have a thyroid nodule until your doctor discovers it during a routine medical exam. Some thyroid nodules, however, may become large enough to be visible or make it difficult to swallow or breathe.