A nodule is a abnormal lump that is usually round in shape. When the node returns only very weak or even zero ultrasound waves, we speak of a hypoechoic nodule. This type of case may require sampling from the hypoechoic organ. They can touch the thyroid, the prostate, the breast or the liver. What are the symptoms ? What examination to know if the hypoechoic nodule is carcinogenic? Should it always be removed?

Definition: what is a hypoechoic nodule?

a nodule East an abnormal lump that is usually round in shape, which develops into an organ. When these nodules are located in organs accessible to ultrasound, such as the thyroid, liver, kidney, breast or prostate, ultrasound will allow to characterize them. Using a probe emitting and receiving ultrasound, we will be able to identify the shape, volume, composition and vascularization of the nodule. “We say that the nodule is hypoechoic if he returns very little, if any, of these ultrasounds during this examination“, explains Dr. Hervé Monpeyssen, thyroidologist, head of the Thyroid Unit at the American Hospital.The meaning of echogenicity depends on the organ examined, sometimes reassuring, sometimes suspicious“, he specifies. In general, we say of a structure that it is hypoechoic when it returns particularly weak ultrasonic waves (or even zero) during an ultrasound. On the screen, the affected area appears darker. Hypoechogenicity may be secondary to fluid disease (formation of cysts or nodules) or liver metastasis. This phenomenon can lead to taking a sample from the hypoechoic organ. The size and volume of the nodule must be accurately assessed: the nodule can measure from a few millimeters to more than ten centimeters. “The size alone is not a sign of suspicion, insists Dr. Monpeyssen, all the factors must be taken into account: the limits of the nodule, its shape, its volume, its vascularization, its rigidity and its score. EU-TIRADS (which is used to classify nodules)”. Apart from pure cysts, all nodules are vascularized. “Rich vascularization is also not a sign of seriousness. A hepatic angioma is a perfectly benign and highly vascularized tumor“, says the doctor.

What are the symptoms of a hypoechoic nodule?

Symptoms depend on the organ where the nodule is located. In the case of a superficial organ (thyroid, breast, etc.), the nodule may appear as a more or less sensitive bump. In case of deep organ (liver, kidney…) the nodule cannot be palpated. It can be discovered and explored on ultrasound.

Where can hypoechoic nodules be located?

► The thyroid nodule is a lump that forms in the thyroid, and can be discovered on palpation by either the patient or the physician. Most often it is discovered during a systematic ultrasound or carotid artery. “It is a very common condition, especially in women: one in two women aged fifty has at least one thyroid nodule“, explains the specialist. In most cases, the nodule is benign in nature and does not cause any symptoms. “Nevertheless, it can become compressive for the other organs of the neck (trachea, esophagus…), or can sometimes be painful.x”, adds the doctor. We say thyroid nodules that they can be “hot” or “cold”. The “hot” nodule means that it is active, and will therefore secrete thyroid hormones in large quantities. It is therefore responsible for hyperthyroidism, but is generally benign. As a reminder, the role of the thyroid is to secrete hormones, which have multiple roles. They regulate our metabolism, control our body temperature, increase heart rate and muscle energy, and even play a role in the utilization of carbohydrates, fats and proteins. Conversely, the thyroid nodule which is said to be “cold” is inactive.

► A prostate lump can be discovered by palpation of the prostate by a urologist. It is an examination recommended from the age of 50 to detect prostate cancer as early as possible. However, not every nodule is necessarily cancer. A prostate biopsy will confirm the diagnosis of prostate cancer when it is suspected.

► A breast lump is a lump or protrusion in the breast. It is recognized by the touch which is different from the rest of the tissue surrounding the breast. A lump may be discovered on the breast during a self-examination or during a clinical examination routinely by a physician. May be more difficult to detect hypoechoic nodules in the breast depending on its density, if it is purely fatty or if it has dense and hypoechoic areas. Breast lumps are relatively common. In general, they are not malignant in nature.

► A nodule in the liver can be discovered during an ultrasound or CT scan. When a nodule, hypoechoic or not, is identified, tests are performed to gauge whether liver function is correct, or whether there is a possible disease such as cirrhosis or hepatitis. Indeed, in the vast majority of cases, nodules develop in a diseased liver: steatosis and cirrhosis. Depending on the disease found (or not), doctors can assign the necessary treatment and prevent possible complications. Indeed, nodules in a diseased liver can become malignant.

When the nodule is detected, the clinician should check the patient for personal characteristics (diseases, treatments, etc.) or family that may be taken into account. “In the case of the thyroid nodule, he must examine it carefully, looking for signs of hyper or hypothyroidism (thyroid that works too much or not enough)“, explains Dr. Monpeyssen. Then at his request, it is the sonographer experienced in the organ concerned which will analyze the ultrasound characteristics. Concerning the thyroid, the sonographer will integrate it into an EU-TIRADS score. “Depending on his score, his size and the elements of the clinical examination, the nodule will or will not be punctured“.

In the case of a malignant or cancerous nodule, surgery remains indisputable

Which examination to analyze the hypoechoic nodule?

To make sure that the nodule is not cancerous, it can be punctured with a fine needle so as to suck up some of its contents in order to analyze it under the microscope. “In the case of the hypoechoic nodule, we generally puncture for a diameter greater than 15 mm, sometimes 10 mm“, says the specialist. The puncture is a simple examination but meticulous, painless which does not require anesthesia and which, in the vast majority of cases, must be performed under ultrasound control. The collected material is sent to a doctor, a cytopathologist, who analyzes the appearance of the cells (this is called cytology) and gives a so-called Bethesda score, separating benign nodules from cancers. In 15% of cases, the nodule is said to be indeterminate and should benefit from other investigations. “For thyroid nodules, scintigraphy finds there one of its indications, the other being the search for a “so-called hot” nodule secreting hormones “for its own account“, explains Doctor Monpeyssen. This diagnostic scheme requires great expertise from the various protagonists. It has made it possible to provide an alternative solution to surgery for most indeterminate nodules.

Should a hypoechoic nodule be removed?

In the majority of cases, we do not touch a benign nodule, up to a size of 4 cm or more. If it is troublesome on a daily basis or very large, especially if it is located on the thyroid gland, you may still have to remove it, to prevent it from hindering swallowing. In the vast majority of cases today, surgery is avoided. The nodule can be treated in other ways: “a purely fluid nodule will simply be evacuated with a needle and alcohol in case of recurrence“, indicates the doctor. “A secreting nodule can easily be treated with radioiodine. A mostly solid nodule can benefit from a thermoablation by laser, radiofrequency or echotherapy (HIFU)“. These are techniques performed on an outpatient basis or in day hospitalization, on a non-sleeping subject. Each nodule is a particular case, and the therapeutic option must be chosen in the interest of the patient, if necessary during a meeting If these alternative techniques are not applicable, in the case of malignant nodules, there remain conventional, minimally invasive and robotic surgical techniques. “In the case of a malignant or cancerous nodule, surgery remains indisputable. In some cases, it can be performed on an indeterminate nodule. Otherwise, we can practice active surveillance and see how it evolves before operating“, concludes the specialist.

Thanks to Dr. Hervé Monpeyssen, thyroidologist, head of the Thyroid Unit at the American Hospital.