Nodules that form on the thyroid may be the result of insufficient iodine, multi-nodular goiter, chronic thyroid inflammation or thyroid cancer, according to Mayo Clinic. Such nodules and may be solid or fluid-filled and also appear due to the unexplained overgrowth of normal thyroid tissue.
While the majority are non-cancerous and do not cause symptoms, malignant nodules tend to be larger and increase in size rapidly. Some may become large enough to be felt or seen as a swelling at the base of the neck, pressing on the windpipe or esophagus to cause shortness of breath or difficulty swallowing.
Patients are advised to have their physician evaluate any unusual swelling as a precaution. Symptoms of hyperthyroidism -sudden weight loss, pounding heart, trouble sleeping, muscle weakness and nervousness or irritability- should also be addressed, advises Mayo Clinic.
In addition to a physical exam, physicians may perform thyroid function tests, ultrsonography, fine-needle aspiration biopsy or a thyroid scan to assess lumps. Benign nodules are typically placed under watchful eye or treated with thyroid hormone suppression therapy; large nodules are surgically removed whether non-cancerous or malignant.
Some nodules may produce excess thyroxine, which leads to unexplained weight loss, intolerance to heat, tremor, nervousness and rapid or irregular heartbeat. When radioactive iodine and anti-thyroid medications are not effective, candidates may be recommended for surgery, explains Mayo Clinic.