A hypoechoic nodule refers to an abnormal protrusion that usually occurs in the thyroid gland. It is a lump, a form of irregularity that is usually observed in the thyroid gland. The thyroid gland is a butterfly-shaped gland that is located in the throat area. These abnormal growths can be either solid or filled with fluid, but in some cases, they are a combination of solid and fluid, in which case they are commonly referred to as complex hypoechoic nodules. The formation of thyroid nodules has often been attributed to a lack of iodine in the diet. Whether a nodule is hypoechoic or not depends on how it appears on ultrasound. As we all know, in an ultrasound test, the transducer placed on the body tissue sends high frequency sound waves into the tissue, which hit the target and return to the transducer as echoes. These echoed sound waves are then used to produce visible images using a scanner. The scanner produces a black and white image on the screen. An ultrasound of the thyroid gland that has a hypoechoic nodule causes sound waves to bounce back in fewer numbers. As a result, the image looks less darker than the normal surrounding thyroid tissue on ultrasound Cancer Risk A majority of papillary cancer―a type of thyroid cancer―are found to be hypoechoic. Also, the chances of hypoechoic nodules being cancerous is somewhat higher than other types of nodules. Moreover, the cancer risk increases if the hypoechoic nodule is found to be a solid mass showing calcified deposits or the ultrasound image suggests that the nodule has its own blood supply. However, most cases of thyroid nodules turn out to be benign. Hence, hypoechoic nodules are usually not a cause for concern. Symptoms As hypoechoic nodules tend to affect the thyroid gland, its functionality is disrupted. The formation of these nodules can either cause hypothyroidism (gland becoming underactive, leading to inadequate production of thyroid hormones) or hyperthyroidism in which the thyroid gland produces more than normal amount of hormones. These thyroid problems can cause fatigue, muscle weakness, and bowel dysfunction that include diarrhea and constipation. The presence of hypoechoic nodules can also affect the larynx (voice box), which may lead to a change in voice. So the person diagnosed with thyroid nodules is likely to complain about hoarseness in his/her voice. Other symptoms that may occur include swollen lymph nodes in the throat area and visible enlargement of the thyroid gland, which may lead to trouble while speaking and swallowing. Diagnosis An ultrasound may detect some suspicious features of hypoechoic nodules, but one should not jump to any conclusions unless a biopsy is carried out. The biopsy test involves using a needle to draw out a sample of cells from the lump. The cells are then observed under a microscope to detect the presence of cancerous cells. This procedure that is carried out under local anesthesia is considered to be a diagnostic test for thyroid cancer. Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.