What Is a Hypoechoic Mass

What Is A Hypoechoic Mass?

Hypoechoic mass (HMG) is a term used to define a collection of cells or tissue within the body which are not part of any organ or system. These cells have no blood supply and therefore do not require oxygen. They may be found throughout the human body but most commonly they occur in the uterus, where they form a mass called a hypoechoic mass (HMG). HMG are usually benign and do not cause symptoms. However, if left untreated they can lead to complications such as infertility and even death.

A common misconception is that these masses must be present before pregnancy occurs; however, it is actually after the conception that the mass becomes visible. Once formed, the mass continues to grow until it reaches a size where its presence causes symptoms such as pain or bleeding. If left untreated, these conditions will progress rapidly into life threatening ones.

The word “hypoechoic” comes from the Greek words hypo meaning under and ekeinos meaning water. Hypoechoic means under the surface of the water. This refers to how these masses are located beneath the skin rather than being at the bottom of a liquid like blood or other fluids.

Hypoechoic mass is also sometimes referred to as submucous mass or submucosal mass.

What Are the Principle Types of HMG?

There are three types of hypoechoic masses which may be present in the uterus:


Fibroids are the most common type of HMG. It is a benign (non-cancerous) tumour which grows from the muscular layer of the uterus. It is most commonly found in women who are of childbearing age (15 to 45 years of age), but it may also be found in pre-pubescent girls and post-menopausal women.

Fibroids are usually present as a single mass but may also appear in multiple forms. They have a hypoechoic appearance on ultrasound which means that they do not show up clearly on the screen. They also appear to have a slightly greyish colour on the ultrasound image.

Fibroids are made up of a combination of muscle and fibrous tissue and grow rapidly throughout pregnancy. Although there is no definite cause for fibroids, certain factors such as genetics and environmental factors may be responsible. Certain viruses and other infections may also play a part in causing their formation.

To diagnose a fibroid, a doctor will use an ultrasound to look for any unusual masses. Other types of scans such as MRI and CT may also be used to detect the presence of fibroids.

The size of the HMG can range from small (less than 2.5 inches in diameter) to very large (larger than 6 inches in diameter). While some types of fibroids are completely benign, others may have some muscle or blood vessel tissue mixed in with them.

These types of HMG are considered to be complex and may be cancerous (malignant).

The most common types of fibroids are:

Submucosal. This is the most common type of fibroid. It arises from the innermost layer of the uterus called the endometrium.

Intramural. This type of fibroid grows into the wall of the uterus but not through it.

Subserosal. This type of fibroid grows under the outermost layer of the uterus (called the serosa).

Interstitial. This type of fibroid grows between the layers of the uterus. They can sometimes grow into the myometrium (muscle layer) or through to the outer covering of the uterus.

Pedunculated. This is a special type of submucosal or subserosal mass where an extension or “peduncle” of tumour tissue attaches the main mass to the inside of the uterus.

Sessile. This is a special type of intramural or submucosal mass where the main mass of the tumour attaches directly into the uterus with no stalks or extensions. Large sessile masses can produce symptoms because of their size alone.

Endometrioid. This is a special type of submucosal mass which contains cells similar to those found in the uterine lining (endometrium).

Functional. This is a special type of intramural or subserosal mass which arises from normal structures of the uterus that have become enlarged or misplaced.

Carcinoid. This is a special type of submucosal mass which arises from cells similar to those which form certain types of cancer (most commonly found in the lungs and digestive tract).

How Are HMG’s Treated?

There are various different ways to treat HMG’s. Treatment will depend on many factors including the type of fibroid, size of the mass, a woman’s age and whether she wishes to become pregnant in the future.

Medical therapy (drug treatment)

If a woman has a submucosal or intramural fibroid which is small and as yet untreated, it may be possible to treat her fibroid(s) with a combination of the hormones oestrogen and progesterone. This therapy helps to reduce the size of the fibroid(s) making them easier to remove with a simple surgery.

Surgical removal

In many cases, surgical removal (a process called myomectomy) of the fibroid may be possible either by an open procedure or using keyhole surgery (known as laparoscopy). Open surgery involves making a cut into the tummy and removing the fibroid through this incision. With laparoscopy a number of small cuts (incisions) are made into the tummy and special instruments and a camera are placed into the abdomen to identify and remove the fibroid.

Laparoscopic myomectomy is a special technique which allows some fibroids to be removed using small incisions. In many cases, it may be possible to remove the fibroid while leaving the uterus intact.

Uterine artery embolization

In some cases a very special type of fibroid called deep fibroids may be found by thorough examination of the pelvis. These fibroids are very difficult to remove surgically and may need to be treated using a special technique called uterine artery embolization.

During this procedure, the fibroid is located and then very small particles (called an embolus) are injected into the blood vessels supplying the fibroid, eventually blocking off the blood supply to the fibroid and destroying it.

Fibroid Embolization is a new technique which has only become available in recent years and is not available everywhere. It may be an option for women whose fibroids are too large to be removed surgically and who do not wish to take the combination of hormones (oestrogen and progesterone) to control the size of their fibroids.

Treating specific symptoms

If a woman has heavy or prolonged bleeding caused by a submucosal or intramural fibroid, it may be possible to treat her symptoms using a special drug called Tranexamic Acid. This drug helps the blood clots to form more quickly therefore decreasing the bleeding. It is given as a tablet and can be taken at home.

If a woman has problems with bladder symptoms (such as difficulty in passing water or needing to pee frequently) it may be possible to treat these using a drug called Tamsulosin. This drug helps the bladder to contract and so increases your ability to pass urine.

If a woman has problems with bowel symptoms (such as difficultly emptying your bowels) it may be possible to treat these using a drug called Ditropan. This drug helps the muscles in the wall of the bowel to relax and contract helping you to empty your bowels.

A woman with severe pain may be given a short course of a strong painkiller. If this is not effective your doctor may refer you to a hospital specialist for further tests to investigate if you have womb cancer.

It is important to remember that most women with fibroids will not have any symptoms and will have no need for any treatment at all. If you do have bothersome symptoms, there are several effective treatments available.

Sources & references used in this article:

Pancreatic and peripancreatic tuberculosis presenting as hypoechoic mass and malignancy diagnosed by ultrasound-guided fine-needle aspiration cytology by RN Rao, R Pandey, MK Rana, P Rai… – Journal of Cytology …, 2013 – ncbi.nlm.nih.gov

Tuberculoma of the liver presenting as a hyperechoic mass on ultrasound. by TC Tan, AY Cheung, WY Wan… – The British journal of …, 1997 – birpublications.org

Hypoechoic testicular mass: a case of testicular and epididymal sarcoidosis by J Rehman, ER Rizkala, B Chughtai, SA Khan – Urology, 2005 – goldjournal.net

Autoimmune pancreatitis detected as a mass in the tail of the pancreas by T Taniguchi, S Seko, K Azuma… – Journal of …, 2000 – Wiley Online Library

Uterine-fundal hypoechoic mass: a possible ultrasound sign for cesarean scar pregnancy by H Takahashi, R Usui, H Suzuki, Y Baba… – Clinical and …, 2017 – ceog.imrpress.com

CASE REPORT: Hypoechoic submucosal nodules: A sign of Epstein‐Barr virus‐associated early gastric cancer by JUN NISHIKAWA, H YANAI… – Journal of …, 1998 – Wiley Online Library