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. Most thyroid nodules aren't serious and don't cause symptoms. Only a small percentage of thyroid nodules are cancerous. You often won't know you have a thyroid nodule until your doctor discovers it during a routine medical exam. Or your doctor may uncover it during a scan that was done for another health reason. Some thyroid nodules, however, may become large enough to be visible or make it difficult to swallow or breathe. Only a small number of thyroid nodules are cancerous. But determining which nodules are cancerous can't be done by evaluating your symptoms alone. Most cancerous thyroid nodules are slow-growing and maybe small when your doctor discovers them. Aggressive thyroid cancers are rare with nodules that may be large, firm, fixed, and rapidly growing.
Most thyroid nodules don't cause signs or symptoms. But occasionally some nodules become so large that they can:
Be felt Be seen, often as a swelling at the base of your neck Press on your windpipe or esophagus, causing shortness of breath or difficulty swallowing
In some cases, thyroid nodules produce additional thyroxine, a hormone secreted by your thyroid gland. The extra thyroxine can cause symptoms of an overproduction of thyroid hormones (hyperthyroidism), such as:
Unexplained weight loss Increased sweating Tremor Nervousness Rapid or irregular heartbeat
A research article reports the results of original research, assesses its contribution to the body of knowledge in a given area, and is published in a peer-reviewed scholarly journal.