Robert Ferry Jr., MD, is a U.S. board-certified Pediatric Endocrinologist. After taking his baccalaureate degree from Yale College, receiving his doctoral degree and residency training in pediatrics at University of Texas Health Science Center at San Antonio (UTHSCSA), he completed fellowship training in pediatric endocrinology at The Children's Hospital of Philadelphia.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Thyroid nodules are more likely to be cancerous at the extremes of age and in males.
The most malignant thyroid cancers are seen at the extremes of age.
Most thyroid cancers are found between ages 20 to 50.
Exposure to radiation also increases the probability that a nodule is cancerous.
A solitary nodule is more likely to be cancerous than multiple nodules.
A nodule arising in a thyroid with normal function is more likely to be cancerous than those arising in a hyperfunctioning gland.
Diagnosis of thyroid cancer is aided by ultrasonography and radionuclide scanning, but is best made by fine needle aspiration (FNA). Cautions with FNA relate to possible incorrect diagnosis or non-diagnostic interpretations from the aspirate(s).
Cancerous and nodules highly suspicious for cancer should be removed. The rest should be followed closely and re-assessed frequently.
Introduction to thyroid nodules
The term "thyroid nodule" refers to any abnormal growth that forms a lump in the thyroid gland.
The thyroid gland is located low in the front of the neck, below the Adam's apple. The gland is shaped like a butterfly and wraps around the windpipe or trachea. The two wings or lobes on either side of the windpipe are joined together by a bridge of tissue, called the isthmus, which crosses over the front of the windpipe.
A thyroid nodule can occur in any part of the gland. Some nodules can be felt quite easily. Others can be hidden deep in the thyroid tissue or located very low in the gland, where they are difficult to feel.
What is the prevalence of thyroid nodules and cancer?
Modern imaging techniques - such as ultrasound (US),
computerized tomography (CT), and magnetic resonance imaging (MRI) - have revealed more thyroid nodules incidentally This means that nodules are being found during studies that were done for reasons other than examination of the thyroid per se. Up to 4% to 8% of adult women and 1% to 2% of adult men have thyroid nodules detectable by physical examination. Closer to 30% of adult women have nodules detectable by ultrasound. In fact, diagnosis of a thyroid nodule is the most common endocrine problem in the United States.
Although the majority of thyroid nodules are benign (not cancerous), about 10% of nodules do contain cancer. Therefore, the primary purpose for evaluating a thyroid nodule is to determine whether cancer is present.
A goiter can develop as a result of numerous different conditions. It can be associated with over-function of the thyroid gland (hyperthyroidism, or excessive thyroid hormones) or with under-function of the gland (hypothyroidism, or inadequate levels of thyroid hormones). Also, some goiters are associated with normal levels of thyroid hormones. Both inflammation and tumors can cause thyroid enlargement. Sometimes, the entire gland may be enlarged in a symmetrical pattern, while in other goiters, nodules, or enlargement may develop in one part of the gland only.