Your friend, a middle-aged woman had been to her family physician for her annual health check-up. To her surprise, the physician finds a swelling at the base of her neck. Though she had not felt any unusual signs or symptoms, the physician suspected some abnormality with her thyroid gland, which is located at the base of the neck. Thus, certain tests were conducted and the diagnosis of a thyroid nodule was made. Your friend is told not to worry, as the nodule was a benign growth, and an appropriate treatment plan can be worked out based on further follow ups.
About Thyroid Nodules
The thyroid gland is a butterfly-shaped structure located at the front of the neck, below the voice box. It produces hormones that regulate the metabolic rate and maintain functioning of the heart. Triiodothyronine (T3) and thyroxine (T4) are the two thyroid hormones. A thyroid nodule is an abnormal growth of thyroid cells in the form of a lump within the gland. A majority of these nodules are benign or non-cancerous (about 90 percent), while a few can be cancerous (8 percent of nodules in men and 4 percent of nodules in women). Hence, it is essential to evaluate a thyroid nodule from the point of view of ruling out a possibility of thyroid cancer. Such nodules are commonly seen as age increases, and observed in around 5 percent of middle-aged and elderly persons, with women being more affected than men.
Causes
The cause for most benign nodules is unknown, but certain factors include lack of iodine in the diet, Hashimoto’s disease which is an autoimmune disorder causing hypothyroidism or decreased activity of the thyroid gland. Other factors are genetic reasons and radiation treatments to the head or neck during childhood. There are different types of thyroid nodules like Colloid nodules, which are one or more overgrowths of normal thyroid tissue, that are benign and do not spread beyond the gland. Thyroid cysts are fluid-filled solid growths within the gland, ranging from 8 millimeters (mm) to 25 mm or more. Inflammatory nodules can result due to chronic inflammation of the gland, while thyroid cancer can lead to formation of nodules in around 5 percent of cases. Multinodular goiter is an enlarged thyroid gland, composed of several nodules and usually benign. There can be hyperfunctioning thyroid nodules that produce thyroid hormones without the influence of thyroid stimulating hormone (TSH) and cause an increase in thyroxine blood levels.
Symptoms
In most cases, the symptoms are not seen, but large nodules or multiple nodules can press against other structures resulting in:
- Breathing difficulty
- Swallowing difficulty
- Goiter (enlargement of the gland)
- Hoarseness or change in voice
- Neck pain
Hyperfunctioning thyroid nodules can sometimes cause symptoms such as:
- Bounding pulse
- Increased appetite
- Nervousness
- Clammy skin (cool, moist, and pale)
- Skin blushing
- Weight loss
- Infrequent, scant menstrual periods
- Disturbed sleep
Hashimoto’s disease results in symptoms of hypothyroidism such as:
- Fatigue
- Unintentional weight gain
- Facial swelling
- Dry skin
- Hair loss
- Cold intolerance
- Frequent, heavy menstrual periods
Though thyroid nodules are seldom cancerous, possible symptoms include fast-growing nodules, which may feel hard. There can be voice hoarseness and trouble while swallowing or breathing. The lymph nodes in the neck and below the jaw may be enlarged.
Diagnosis
In most cases, thyroid nodules are found during a routine physical examination. Certain laboratory tests will then be conducted to determine whether there is hyperfunctioning (production of more thyroid hormone) or hypofunctioning (production of less thyroid hormone) of the thyroid gland. Such thyroid function tests can measure the blood levels of T3, T4, and TSH. To ascertain whether the nodule is benign or malignant, tests include Fine needle aspiration (FNA) biopsy where a thin needle is inserted to obtain samples of cells. Examination under a microscope will reveal whether there is malignancy or there is suspicion of malignancy. An ultrasound may also be performed to determine whether the nodule is a solid tumor or a cyst filled with fluid. At times, this procedure is used to help aspirate cells or fluid as a clear picture of the nodule is seen and is known as ‘ultrasound guided fine needle aspiration biopsy.’ A thyroid scan may be done, where radioactive iodine is injected into a vein of the arm. The gland absorbs the iodine and the degree of absorption by the nodules helps in determining if the nodules are benign or malignant.
Treatment
When the nodule is non-cancerous, the condition is only monitored through timely check-ups. If the nodule does not grow further, there is not much reason to worry. At times, thyroid hormone suppression therapy is used when a benign nodule needs to be shrunk. Here, levothyroxine, a synthetic form of hormone thyroxine, given orally signals the pituitary gland to produce less TSH. This therapy is still under debate with regards to the results seen. Radioactive iodine can be used to treat hyperfunctioning nodules and multinodular goiters, which results in shrinking of the nodules. This treatment is contraindicated in pregnant women and those trying to conceive. Another method to shrink the nodules is by alcohol ablation, where ethanol is injected in hyperfunctioning nodules. In malignant or suspicious cases, surgery is the best option. Here, the cancerous tissue along with some thyroid tissue (near-total thyroidectomy) is removed. Most thyroid cancers can be cured and rarely cause serious problems.
Being alert
Benign cases of thyroid nodules are not life-threatening, and may not require any treatment. Regular observation (every 6 months) is necessary and some may just resolve. Since the exact cause of nodules is indefinite, having enough iodine in the diet can prevent such nodules from developing. Having a family history of thyroid disorders or any history of radiation exposure should be kept in mind. If at any time, you feel or see a lump in your neck, or experience any symptoms of a thyroid nodule, get examined promptly by an endocrinologist (a specialist in hormone-related conditions). Keeping to the recommended treatment and follow-ups will help resolve the condition.
