Mauro Czepielewski, MD., Ph.D. in Endocrinology – São Paulo State University School of Medicine (UNIFESP). Vice-Director of the State University Rio Grande do Sul School of Medicine (UFRGS). Associate Professor – Internal Medicine Department/UFRGS.
What is it?
They’re ovoid lesions that develop in the thyroid gland, located in the anterior and lower region of the neck. There may be one nodule or multiple nodules. When there’s only one single nodule, these are called solitary nodule or uninodular goiter. When multiple, they constitute a multinodular goiter. They’re caused by benign tumors, malignant tumors, cysts, inflammatory diseases (thyroiditis), and colloid nodular goiter.
How does it develop?
Depending upon the cause, the nodules are caused by several conditions.
Single or solitary nodules may be due to:
|Benign tumors (follicular adenomas),|
|Colloid nodular goiter, or, more rarely,|
When multiple, they generally result from a colloid nodular goiter or inflammatory processes (thyroiditis). When there’s a nodule that is larger than the others (dominant nodule), its cause may be the development of a malignant tumor, especially amongst us, where areas deprived of iodine still exist. Lack of iodine in the diet may lead to endemic goiter (see specific item on this site), whose progress leads to a nodular goiter (formation of several nodules). Among these nodules, one of them may evolve into malignant thyroid neoplasia, a condition in which a progressive growth of a nodule will be observed, forming the so-called “dominant nodule”.
What does one experience?
In general, nodules are asymptomatic, eliciting local symptoms when they become highly enlarged.
These symptoms are:
|Difficulty swallowing food,|
|Hoarseness; hoarse voice with two tones,|
|Dilatation of the neck’s veins,|
|And ,quite rarely, local pain.|
In addition to local symptoms, signs and symptoms of decrease (hypothyroidism) or enlargement (hyperthyroidism) of the thyroid gland may take place. These alterations are described in specific items on this web site.
In single or solitary nodules, it’s important to define those at greater risk of developing cancer. The patients at higher risk for thyroid cancer belong to the male gender; are under the age of 30 and above 60; present with recurrent initial nodule of progressive growth; and received radiotherapy to the face or neck, with the nodule showing hard consistency on palpation and being attached to other structures of the neck, which presents similarly palpable lymph nodes. The patient also presents with hoarseness or difficulty swallowing food.
How does the doctor diagnose it?
The diagnosis is established by clinical history and a suitable clinical evaluation including a thorough exam of the neck and an investigation into signs and symptoms of decrease or increase of the thyroid gland’s functional activity.
Based on the initial medical evaluation, the patient must undergo a thyroid function test for the levels of their hormones, initially by gauging TSH, and, if necessary, T4; rarely T3.
Besides this, it’s equally useful to perform an echography of the neck for thyroid gland features, which will determine whether there’s one or more nodules in the gland, and what the features of these nodules are.
In the presence of normal hormone levels and a single nodule, a needle biopsy of the nodule must be carried out, which will elucidate its origin in detail. If there are several nodules, with one of them standing out, this must be aspirated for a detailed diagnosis.
In cases in which hyperthyroidism is suspected, the patient may need to undergo thyroid scintigraphy.
In cases of diffuse goiter and suspicion of hypothyroidism, a test for anti-thyroid antibodies (antithyroperoxidase antibodies- AntiTPO, or antimicrosomal antibodies) must be conducted with the purpose of detecting the presence or absence of Hashimoto’s thyroiditis.
How is it treated?
In cases where malignant neoplasia is suspected, a surgery for complete removal of the thyroid gland is indicated, supplemented by treatment with radioactive iodine and thyroid hormone (see specific item on this site). In bulky goiters with cervical compressive manifestations, surgery is also indicated. For patients with single or multiple nodules, drug treatment and, especially, the administration of therapeutic doses of radioactive iodine can be indicated. In hypothyroidism patients, a thyroxine (T4) hormone replacement therapy is indicated, with suitable doses corrected for bodyweight.
How is it prevented?
The nodules that can be prevented are those associated to endemic goiters (arising from iodine deficiency). In presence of solitary or multiple nodules and a history of first-degree relatives also carrying the same alteration, an early investigation into family neoplasias through hormone or molecular markers must be undertaken.