Thyroid Nodules

Thyroid nodules are extremely common, with estimates suggesting that up to 50% of the population may develop them. They occur more frequently in women and are more often benign than malignant. Most nodules are not visible or palpable and are usually discovered incidentally during an ultrasound. In most cases, thyroid hormone levels remain normal despite the presence of nodules.

If a thyroid scintigraphy is performed (which is not always necessary), nodules may appear as “hot” (overactive) or “cold” (underactive). Cold nodules carry a higher risk of malignancy, although hot nodules are not entirely risk-free.

Modern medicine has not fully clarified the exact mechanisms behind nodule formation. Certain recognized factors include:

• Overgrowth of normal thyroid tissue

• Iodine deficiency

• Chronic thyroid inflammation, such as in Hashimoto’s thyroiditis

• Development of thyroid cysts

• Use of certain medications affecting thyroid function

• Genetic predisposition and family history

• Environmental factors such as smoking, obesity, metabolic syndrome, and alcohol consumption

• History of therapeutic radiation to the head or neck

In the vast majority of cases, thyroid nodules cause no symptoms and are painless, often growing silently. 

Symptoms may occur if nodules exert pressure on nearby structures:

• Discomfort in the neck

• Visible or palpable swelling at the front of the neck

• Difficulty swallowing (dysphagia)

• Choking sensation if the esophagus is compressed

• Shortness of breath or pressure in the throat

• Hoarseness or voice changes

• Cough or sensation of a foreign body in the throat

• Feeling of heaviness or pain in the neck

If nodules cause hyperthyroidism, symptoms may include:

• Rapid heartbeat or arrhythmias

• Anxiety, nervousness, or insomnia

• Hand tremors

• Weight changes

• Sweating and heat intolerance

• Menstrual irregularities (in women)

• Changes in bowel habits

When thyroid nodules start causing noticeable symptoms, the disease is no longer at an early stage, and prompt intervention is required.

Beyond medical history and clinical examination of the neck, the thyroid ultrasound is the gold-standard diagnostic tool. 

Ultrasound evaluates the nodule’s size, composition (solid or cystic), relation to surrounding structures, suspicious features for malignancy, and presence of abnormal lymph nodes. Elastography may also be performed to assess nodule stiffness and potential malignancy. Further evaluation is performed with fine-needle aspiration (FNA) of the nodule.

Additionally, hormonal tests are carried out (TSH, T3, T4, Tg, Anti-TG, Anti-TPO, Calcitonin), and in certain cases, a thyroid scintigraphy, CT or MRI scans, PET scan, etc., may be requested.

Fine Needle Aspiration (FNA) biopsy is a technique that was first described in Sweden, almost half a century ago, for the evaluation of swellings in the thyroid gland. It is based on the removal of cells from the thyroid via the needle, with or without local anaesthesia, and their further examination under a microscope.

The findings of the examination may be characterized as benign, malignant, suspect of malignancy or insufficient for diagnosis.

Fine Needle Aspiration is a frequently used method for examining thyroid nodules, providing important information, however the information as to whether we have to do with a benign nodule or cancer is based on the examination of a very small sample of cells and cannot offer us the certainty that the neighbouring cells are not cancer as well.

I have had one or more fine-needle aspirations (FNA) that showed benign results. Can I safely assume that I do not have cancer

Punctures suck out a small number of cells from specific points of the nodules and usually it is the larger nodules that are punctured because this is easier for the one performing the examination.

Very often however, patients with one or many “clean” pre-surgical fine needle aspiration biopsies, do have, in the end, after the surgery, a biopsy positive for cancer. This is explained by the needle finding itself just a few millimetres beside the cancerous focus and the correct diagnosis failed to be made.

Therefore, the F.N.A. result has simply indicatory and not proving value. The certainty that there is cancer or not can only be provided by a biopsy of a thyroid that has been excised and examined.

A nodule, even one only a few millimeters in size, contains millions of cells. Leaving a pathological focus (nodule) in the body, which may not have significantly decreased or disappeared despite treatment, allows for the possibility of malignant transformation at any time.

The transformation of a nodule from benign to malignant typically does not cause symptoms and usually does not affect thyroid hormone tests.

The size of a nodule does not constitute a defining criterion to diagnose malignancy. Some of its ultrasound characteristics, such as the calcifications, the boundaries, the vascularity and in general the morphology of a nodule may be grounds for suspicion of neoplasia. There are many patients that decided to undergo surgery due to a large (e.g. 2.5 cm) nodule and in the end the biopsy “absolved” the large nodule, but found multiple cancerous foci in other, seemingly insignificant, of few millimetres, nodules.

Thyroid nodules usually do not resolve or shrink on their own, as the underlying cause remains active throughout life. Even when serial ultrasounds appear to show a nodule has decreased in size, this is often due to slight differences in probe placement by the operator rather than a true reduction.

Thyroid nodules are established lesions that are not expected to disappear spontaneously. Fluctuations in size may occur due to changes in the fluid (colloid) they may contain, while the solid component persists and usually grows.

Their presence requires regular medical monitoring or definitive removal.

Dr. Evangelos Karvounis, MD, PhD, FACS, is an award-winning endocrine surgeon, Doctor of the Medical School of the University of Athens and Fellow of the American College of Surgeons.
With extensive experience, specialized training in robotic surgery, and a rich research and publication record, he can answer all your questions about thyroid nodules, including when they may be malignant and how they are treated.

As Director of Endocrine Surgery at Euroclinic Athens, he applies cutting-edge microsurgical techniques, making him a top choice for safe and effective thyroid and parathyroid procedures. Trust his patient-centered, personalized approach and schedule your appointment today for safe treatment and rapid recovery.