Thyroid Nodules (cont.)
Robert Ferry Jr., MD
Robert Ferry Jr., MD
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
Melissa Conrad Stöppler, MD
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.
In this Article
What is a goiter?
A goiter is simply an enlarged thyroid gland. Multiple conditions can lead to goiter, including hypothyroidism, hyperthyroidism, excessive iodine intake, or thyroid tumors. Goiter is a non-specific finding that warrants medical evaluation.
How are thyroid nodules diagnosed?
Thyroid nodules usually are discovered by the health care professional during routine physical examination of the neck. Occasionally, a patient may notice a nodule as a small lump in their neck when looking in the mirror. Once a nodule is discovered, a physician will carefully evaluate the nodule.
History: The doctor will take a detailed history, evaluating both past and present medical problems. If the patient is younger than 20 or older than 70 years, there is increased likelihood that a nodule is cancerous. Similarly, the nodule is more likely to be cancerous if there is any history of radiation exposure, difficulty swallowing, or a change in the voice. It was actually customary to apply radiation to the head and neck in the 1950s to treat acne! Significant radiation exposures include the Chernobyl and Fukushima disasters. Although women tend to have more thyroid nodules than men, the nodules found in men are more likely to be cancerous. Despite its value, the history cannot differentiate benign from malignant nodules. Thus, many patients with risk factors uncovered in the history will have benign lesions. Others without risk factors for malignant nodules may still have thyroid cancer.
Physical examination: The physician should determine if there is one nodule or many nodules, and what the remainder of the gland feels like. The probability of cancer is higher if the nodule is fixed to the surrounding tissue (unmovable). In addition, the physical exam should search for any abnormal lymph nodes nearby that may suggest the spread of cancer. In addition to evaluating the thyroid, the physician should identify any signs of gland malfunction, such as thyroid hormone overproduction (hyperthyroidism) or underproduction (hypothyroidism).
Blood tests: Initially, blood tests should be done to assess thyroid function. These tests include:
Ultrasonography: A physician may order an ultrasound examination of the thyroid to:
Despite its value, the ultrasound cannot determine whether a nodule is benign or cancerous.
Radionuclide scanning: Radionuclide scanning with radioactive chemicals is another imaging technique a physician may use to evaluate a thyroid nodule. The normal thyroid gland accumulates iodine from the blood and uses it to make thyroid hormones. Thus, when radioactive iodine (123-iodine) is administered orally or intravenously to an individual, it accumulates in the thyroid and causes the gland to "light up" when imaged by a nuclear camera (a type of Geiger counter). The rate of accumulation gives an indication of how the thyroid gland and any nodules are functioning. A "hot spot" appears if a part of the gland or a nodule is producing too much hormone. Non-functioning or hypo-functioning nodules appear as "cold spots" on scanning. A cold or non-functioning nodule carries a higher risk of cancer than a normal or hyper-functioning nodule. Cancerous nodules are more likely to be cold, because cancer cells are immature and don't accumulate the iodine as well as normal thyroid tissue. However, cold spots can also be caused by cysts. This makes the ultrasound a much better tool for determining the need to do an FNA.
Fine needle aspiration: Fine needle aspiration (FNA) of a nodule is a type of biopsy and the most common, direct way to determine what types of cells are present. The needle used is very thin. The procedure is simple and can be done in an outpatient office, and anesthetic is injected into tissues traversed by the needle. FNA is possible if the nodule is easily felt. If the nodule is more difficult to feel, fine needle aspiration can be performed with ultrasound guidance. The needle is inserted into the thyroid or nodule to withdraw cells. Usually, several samples are taken to maximize the chance of detecting abnormal cells. These cells are examined microscopically by a pathologist to determine if cancer cells are present. The value of FNA depends upon the experience of the physician performing the FNA and the pathologist reading the specimen. Diagnoses that can be made from FNA include:
One of the most difficult problems for the pathologist is to be confident that a follicular adenoma - usually a benign nodule - is not a follicular cell carcinoma or cancer. In these cases, it is up to the physician and the patient to weigh the option of surgery on a case-by-case basis, with less reliance on the pathologist's interpretation of the biopsy. It is also important to remember that there is a small risk (3%) that a benign nodule diagnosed by FNA may still be cancerous. Thus, even benign nodules should be followed closely by the patient and physician. Another biopsy may be necessary, especially if the nodule is growing. Most thyroid cancers are not very aggressive; that is, they do not spread rapidly. The exception is poorly differentiated (anaplastic) carcinoma, which spreads rapidly and is difficult to treat.
Medically Reviewed by a Doctor on 2/11/2015
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