The thyroid is a butterfly-shaped gland located at the base of the neck, under the Adam’s apple. It makes essential thyroid hormones for the control of basic metabolism, a metabolism that provides the energy needed by the body to maintain its vital functions: heart, brain, breathing, digestion, maintaining body temperature.
It is not uncommon for a small mass to form in the thyroid gland, for reasons that are still often unknown. It is given the name of thyroid nodule (from the Latin nodulus , small node).
Thyroid nodules are very common: between 5 and 20% of the population has a nodule of more than 1 cm perceived on palpation and if we count non-palpable nodules identified only by ultrasound, 40 to 50% of the population has a thyroid nodule. For probably hormonal reasons, nodules are about 4 times more common in women than in men.
Nodules are most often accompanied by no symptoms. And if 95% of thyroid nodules are benign, 5% are cancerous. Some nodules, however benign (non-cancerous) are toxic (5 to 10%), that is to say they produce excess thyroid hormones. More rarely, the nodule can be troublesome by its volume and become compressive (2.5%)
The palpation of the neck should be systematic during the consultation with the general practitioner, the gynecologist … etc.
It is therefore important to make an accurate diagnosis of the origin of a nodule to understand what type of nodule it is, whether it should be treated and how.
Types of nodules at the thyroid
- Colloidal nodule. The most common form of nodule, the colloidal nodule consists of normal cells.
- Cysts. Cysts are formations filled with fluid. They can reach up to several centimeters in diameter. They are, for the most part, benign.
- Inflammatory nodule. It occurs most often in people with thyroiditis, an inflammation of the thyroid. Thyroiditis can occur as a result of an autoimmune disease (a condition where the body develops antibodies against its own organs), such as Hashimoto’s thyroiditis. It can also occur after a pregnancy.
- Adenoma. It is a benign tumor. Anatomically, the tumor tissue is very similar to the healthy tissue of the thyroid gland. To distinguish the adenoma from cancer, a biopsy is necessary.
- Thyroid cancer. The malignant (or cancerous) nodule represents 5% to 10% of the thyroid nodules. Thyroid cancer is a rare cancer. There are 4000 new cases per year in France (for 40 000 breast cancers). It concerns women in 75% of cases. Its incidence is increasing in all countries. Nodules are more common in women, but men have an increased risk of developing cancer in a thyroid nodule. People who have a history of thyroid disorders or who have received radiation therapy to their head or neck during their childhood are at higher risk. This cancer is most often treated very well with a survival rate after 5 years exceeding 98%.
|Goiter or nodule?
Goiter is different from a nodule because it affects the entire thyroid gland that increases in volume. The nodule, meanwhile, is characterized by a small mass circumscribed on the thyroid. But in some goiters, the increase in volume is not homogeneous, concerning only certain areas of the thyroid, then constituting a so-called nodular goitre or multi-nodular (see goiter sheet)
Symptoms of the thyroid nodule
The vast majority of thyroid nodulescause no symptoms. Most are discovered when the doctor palpates the neck at the time of a consultation.
Sometimes it is the affected person or his entourage who finds this small mass.
When the nodule is bulky, it can cause a feeling of pressure in the neck sometimes painful, difficulty swallowing or breathing.
If the nodule produces too much thyroid hormone, then it shows signs of hyperthyroidism : weight loss, heart palpitations, sleep disorders, muscle weakness, diarrhea, nervousness or irritability .
When to consult?
- If you notice a small visible or palpable mass at the base of the neck,
- If there is swelling of the neck glands,
- If you swallow with difficulty,
- If you lose weight despite a normal or increased appetite
People at risk for Thyroid nodule
- Older people because nodules become more common with advancing age: 20% of people 30 years have a nodule detectable in ultrasound, and 50% at 60 years.
- The women.
- People with iodine deficiency.
- People with a close relative who has a thyroid nodule.
- People who have already had a thyroid abnormality (eg, thyroiditis).
- People who have already received radiation therapy to the head or neck.
- People who have been exposed to radioactive particles from nuclear tests or accidents, such as that of Chernobyl in 1986 or more recently from Fukushima. In their case, there is an increased risk of thyroid cancer . The effects can be felt up to several thousand kilometers away from the radioactive emanation. The impacts on the thyroid may appear several years after exposure.
Elements that may give rise to a suspicion of a cancer risk in the presence of a thyroid nodule:
- Age: under 16 or> over 65
- History of Thyroid Cancer Tumor
- Nodule recently appeared or rapidly evolutive
- Hard, irregular, or fixed nodule
- History of cervical irradiation
- Proximal lymphadenopathy
– Iodine deficiency should be avoided as it is a risk factor for thyroid nodules.
– Irradiation treatments are increasingly adapted to deliver only the minimum dose required in each case, and limit the impact on the thyroid.
The diagnosis of Thyroid nodule
The doctor first determines, by means of various examinations, the nature of the nodule. Treatment or no treatment is chosen accordingly. Before the 1980s, the majority of nodules were removed by surgery. Since then, diagnostic and treatment methods have been refined to operate only when necessary.
The examination of the neck will confirm whether the swelling is indeed related to the thyroid, whether it is painful or not, single or multiple, of hard, firm or soft consistency, and to look for the presence of ganglions in the neck
General examination looks for signs of abnormal thyroid function
The doctor will also ask what the treatments are usually taken by the person, the notion of antecedents of thyroid problems in the family, radiation of the neck in childhood, the geographical origin, the contributing factors (tobacco, lack in iodine, pregnancy)
Determination of thyroid hormones
The blood test of the hormone TSH regulating the production of thyroid hormones makes it possible to check whether the secretion of thyroid hormones is normal, excessive (hyperthyroidism) or insufficient (hypothyroidism). The dosage of thyroid hormones T3 and T4 is required only if the TSH is abnormal. The presence of anti-thyroid antibodies is also sought. Calcitonin is required if you suspect a particular form of cancer, medullary thyroid cancer.
This is the preferred method for the diagnosis of thyroid nodules. It allows to visualize the nodules of 2 mm of diameter or more and to know the number of nodules and the possible presence multinodular goiter. Imaging is also used to differentiate the solid, liquid or mixed aspect of the nodule. Depending on its appearance and size, it gives arguments in favor of the benign or malignant character that lead to ask or not a puncture. It also allows after treatment to follow the evolution of the nodule.
It is only required when the dosage of TSH hormone is low.
To make a thyroid scintigraphy, after taking radioactive markers such as iodine or technetium, one observes how iodine is distributed in the thyroid gland.
This examination specifies the overall functioning of the gland, can show unconscious nodules on palpation and looks for whether the nodules are “cold” it is with decreased thyroid hyperfunction, “hot” with excessive manufacture of hormones, or “neutral” “with normal hormonal function.
A hot nodule is almost always benign, so it is not a priori a cancer. Cold nodules are a little more often cancers, even if 90% are still benign.
The puncture of a nodule under ultrasound control is requested if the clinical characters or the appearance on ultrasound make suspect the malignancy of the nodule. Using a thin needle, the doctor draws the nodule cells for a microscopic examination of their characteristics and assesses the nature , benign or cancerous nodule. It also allows to evacuate a cystic nodule.
The puncture will be renewed if it is not conclusive
These examinations can be supplemented by a thyroid scan, a CT scan or an MRI. When a thyroid cancer is suspected, it is often the surgical procedure with histological examination of the tumor that allows or not to confirm it.
Treatments of Thyroid nodule
Radioactive iodine. It is often used in addition to thyroid cancer surgery to destroy all thyroid cells that may not have been removed by surgery.
Radioactive iodine is also used to treat nodules (“hot”) causing symptoms of hyperthyroidism. A treatment of 2 to 3 months is usually enough for the nodules to subside and the symptoms of hyperthyroidism to disappear. Iodine is taken orally in the form of capsules or liquid. This treatment causes permanent hypothyroidism in about 80% of cases because radioactive iodine destroys hormone-producing cells. This hypothyroidism secondary to the treatment can be well compensated by treatment with thyroid hormones then taken regularly. In some cases, the nodules are treated by surgery.
Surgery . It removes a lobe or the entire thyroid (thyroidectomy). It is indicated when nodules are cancerous or suspected of malignancy, or if they are hypersecreting (producing too much thyroid hormone) or bulky. A thyroid hormone replacement therapy (levothyroxine) for life is most often required. Thereafter, the person operated will therefore take thyroid hormone replacement every day.
Nodules without hormonal secretions and volume less than ¾ cm are monitored every 6 months to one year.