A thyroid nodule is defined as a lesion or a growth that occurs in the thyroid gland. These growths or nodules are completely benign and pose no real threat to the health of the individual. Anatomically speaking, thyroid gland is located in the front of the neck. The main function of this gland is to produce hormones that regulate the metabolism of the body. The primary reason for a nodule to develop on the thyroid is due to growth of a tissue or a cyst. The risk of the nodules becoming cancerous even though is quite low but there are some thyroid nodules which have somewhat of a higher risk than others. Of this, one is hypoechoic thyroid nodule.
There is little data in the literature about the natural course of Hypoechoic Thyroid Nodules and based on FNAC results it is not quite clear about the percentage of people who have this nodule go on to develop cancer of the thyroid.[1,2] In this article, we explore what hypoechoic thyroid nodules are, how they influence cancer risk, and what can be done about it.
What Is Hypoechoic Thyroid Nodule?
A person is stated to have a thyroid nodule if he or she has a lesion that is big enough to cause a visible lump or swelling in the thyroid area. A thyroid nodule can be easily seen during a routine checkup or an imaging study in and around the thyroid gland. Once a thyroid nodule is identified, the physicians then do an ultrasound examination to look for any special characteristics of the nodule and also perform a risk assessment for thyroid cancer.
During ultrasound, physicians look for what is termed as echogenicity of the thyroid nodule. By echogenicity, we mean the brightness of the nodule with respect to the surrounding tissue. In some cases, the nodule appears darker. This is what is called as hypoechoic thyroid nodule. A hypoechoic thyroid nodule suggests that the lesion is solid and not fluid filled as most of thyroid lesions are.
Coming to the risk of cancer, the American Thyroid Association states that 95% of all thyroid nodules are benign and not cancerous. However, they also mention that people with hypoechoic thyroid nodule have higher chances of malignancy than people which have fluid filled nodules.
However, other characteristics such as the size also play a role in assessing the risk of a nodule developing into cancer. A fine needle biopsy is necessary to check for cancer in cases where a physician suspects any malignancy in the thyroid.
What Can Be Done About Hypoechoic Thyroid Nodule?
Whenever a Hypoechoic Thyroid Nodule is detected on ultrasound, it is imperative for physicians to send the patient for further testing to include:
Blood Tests: This will be done to check the functioning of the gland. Blood testing will measure the levels of TSH and thyroxine which will clearly show whether the patient is hyper or hypothyroid or whether the levels are normal.
Fine-Needle Biopsy: This test is done especially for people who have a Hypoechoic Thyroid Nodule. This test is done by inserting a fine needle through the neck under ultrasound guidance and into the nodule and taking a small sample of the tissue. This will be then analyzed in the laboratory to look for any malignancy. If any malignancy is observed, then further treatment plan is made by the physician.
Surgery: A hypoechoic thyroid nodule may require surgery to be removed if the physician suspects any malignancy on biopsy of Hypoechoic Thyroid Nodule. The surgery involves removal of the entire or the diseased portion of the thyroid gland. If the entire gland is removed then such patients will have to take hormone replacement medicines throughout their lives to prevent any case of underactive thyroid.
Surgery is more or less curative if the cancer has not spread to other parts. However, additional treatments will be required in cases where there has been a spread of cancer to include radiation and chemotherapy or radioactive iodine therapy. In some cases, Hypoechoic Thyroid Nodules can cause changes in the voice of a person or problems with swallowing or breathing. This is also a situation where surgery is recommended.
In conclusion, thyroid nodules are overgrowths that develop in the thyroid gland. These nodules have different characteristics which are best seen when an ultrasound is done of the thyroid gland. One such characteristic is Hypoechoic Thyroid nodule. These nodules appear darker with respect to the remaining tissue on the ultrasound meaning that they are solid and not fluid filled nodules like a cyst.
Majority of the thyroid nodules are benign and have very low risk of going on to develop into cancer. However, people with Hypoechoic Thyroid Nodule are at a slightly higher risk. People with Hypoechoic Thyroid Nodule undergo additional testing in the form of a fine needle biopsy to check for any chances of malignancy. If a cancerous lesion is identified then the patient will be given treatments as detailed above. Surgery to remove the gland partially or completely is the primary treatment for malignant Hypoechoic Thyroid Nodules.