Leiomyosarcomas (LMS)

Leiomyosarcoma (LMS) is a type of soft tissue sarcoma. Soft tissue sarcomas can develop in muscle, fat, blood vessels, or any of the other tissues that support, surround and protect the organs of the body.

Leiomyosarcoma is one of the more common types of soft tissue sarcoma to develop in adults. We don’t yet know the exact cause.

Leiomyosarcomas are usually treated at a specialist hospital. The usual treatment for a leiomyosarcoma is surgery to remove the tumour. You may have radiotherapy after surgery, to reduce the chance of the cancer coming back. Chemotherapy is also sometimes used for a leiomyosarcomas that has come back, or that has spread.

You may be asked to take part in clinical trial looking at new ways of treating leiomyosarcomas. Your doctor or specialist nurse can talk to you about this.

After treatment, you will have regular check-ups. If you have any problems or notice any new symptoms between these check-ups, it’s important to let your doctor know as soon as possible.

What is leiomyosarcoma (LMS)?

Leiomyosarcoma (LMS) is a type of soft tissue sarcoma. The information here should ideally be read with our general information about soft tissue sarcomas.

We hope this information answers your questions. If you have any further questions, you can ask your doctor or nurse at the hospital where you're having your treatment.


Sarcomas are rare types of cancer that develop in the supporting or connective tissues of the body. There are two main types, soft tissue sarcomas and bone sarcomas.

Soft tissue sarcomas can develop in muscle, fat, blood vessels, or any of the other tissues that support, surround and protect the organs of the body.

Bone sarcomas can develop in any of the bones of the body, but may also develop in the soft tissue near bones.


Soft tissue sarcomas are rare. Only about 3,300 new cases are diagnosed each year in the UK. There are several different types of soft tissue sarcoma.

Leiomyosarcomas are one of the more common types of sarcoma to develop in adults. They start from cells in a type of muscle tissue called smooth muscle.

Smooth muscles are involuntary muscles that we have no control over. They are found in the walls of muscular organs like the heart and stomach, as well as in the walls of blood vessels throughout the body. This means that leiomyosarcomas can start anywhere in the body. Common places are the walls of the womb (uterus), the trunk of the body, and the arms and legs.

Causes of leiomyosarcoma

The exact causes of leiomyosarcomas are unknown. Researchers are trying to find out as much as possible about them.

Most people with leiomyosarcoma are over the age of 50.

Soft tissue sarcomas may occur in an area that has previously been treated with radiotherapy for another type of cancer. The sarcoma won’t usually develop until at least 10 years after the radiotherapy treatment.

Exposure to some types of chemicals may increase the risk of developing some sarcomas. The chemicals include vinyl chloride (used for making plastics), some types of herbicides (weed killers) and dioxins.

Signs and symptoms of leiomyosarcoma

People with early leiomyosarcoma often don’t have any symptoms. Most leiomyosarcomas are diagnosed after a person develops symptoms. These may include:

  • a lump or swelling
  • abdominal discomfort or bloating
  • swelling or pain in any area of the body
  • bleeding from the vagina in women who have had the menopause, or a change in periods for women who have not yet had the menopause.

If you notice any of these symptoms, you should contact your GP. Remember that these symptoms can also be caused by conditions other than cancer.

How leiomyosarcoma is diagnosed

Usually you begin by seeing your family doctor (GP), who will examine you. You will be referred to a hospital specialist for any tests that may be necessary and for expert advice and treatment. The doctor at the hospital will take your full medical history, do a physical examination and take blood samples to check your general health.

The following tests are commonly used to diagnose a leiomyosarcoma. The tests you have will depend on the part of the body being investigated. You may have had some of these tests already. If you’re having investigations other than those listed, our cancer support specialists can give you further information.


This test is used to diagnose problems in the womb. The doctor uses a small, thin tube with a light and camera at the end (hysteroscope) to look into the womb and take tissue samples (biopsies) to be looked at under a microscope. The hysteroscope is passed through your vagina and into your womb. You may have this test as an outpatient under local anaesthetic, but sometimes a general anaesthetic is needed.

A hysteroscopy may be uncomfortable but should not be painful. Some women may have mild cramping during the procedure and for a few days afterwards. You may be advised to take mild painkillers, such as paracetamol, 30 minutes before the procedure.

Ultrasound scan

This test uses sound waves to create a picture of the abdomen and surrounding organs. It is done in the hospital's scanning department. You will be asked not to eat, and to drink only clear fluids (nothing fizzy or milky) for 4-6 hours before the scan.

Once you’re lying comfortably on your back, a gel is spread over your abdomen. A small device like a microphone (called a probe) is then rubbed over the area. It emits sound waves that are then converted into a picture using a computer. The test should not be painful and takes about 15-20 minutes.

If a uterine sarcoma is suspected, the probe will also be inserted gently into the vagina to examine the womb more closely.

Ultrasound may also be used to look for a suspected cancer in a limb.

CT (computerised tomography) scan

A CT scan takes a series of x-rays, which build up a three-dimensional picture of the inside of the body. The scan takes 10 to 30 minutes and is painless. It uses a small amount of radiation, which is very unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan.

CT scan
CT scan

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You may be given a drink or injection of a dye, which allows particular areas to be seen more clearly. This may make you feel hot all over for a few minutes. It is important to let your doctor know if you are allergic to iodine or have asthma, because you could have a more serious reaction to the injection.

You will probably be able to go home as soon as the scan is over.

MRI scan

This test uses magnetism to build up a detailed picture of areas of your body. The scanner is a powerful magnet so you may be asked to complete and sign a checklist to make sure it is safe for you. The checklist asks about any metal implants you may have, such as a pacemaker, surgical clips or bone pins, etc.

You should also tell your doctor if you have ever worked with metal or in the metal industry as very tiny fragments of metal can sometimes lodge in the body. If you do have any metal in your body, it is likely that you will not be able to have an MRI scan. In this situation, another type of scan can be used. Before the scan, you will be asked to remove any metal belongings including jewellery.

Some people are given an injection of dye into a vein in the arm, which does not usually cause discomfort. This is called a contrast medium and can help the images from the scan to show up more clearly. During the test, you will lie very still on a couch inside a long cylinder (tube) for about 30 minutes. It is painless but can be slightly uncomfortable, and some people feel a bit claustrophobic. It is also noisy, but you will be given earplugs or headphones. You can hear, and speak to, the person operating the scanner.


The results of the previous tests may make your doctor strongly suspect you have cancer. The only way to be sure is to take some cells or a small piece of tissue from the affected area to look at under a microscope. This is called a biopsy. The area is numbed using a local anaesthetic injection and then a fine needle is passed into the tumour through the skin. A CT or ultrasound scan may be used at the same time to make sure that the biopsy is taken from the right place. Sometimes the biopsy is taken during a hysteroscopy (see above).

When the cells are looked at under a microscope, the specialist will be able to tell whether they are benign (not cancerous) or malignant (cancerous). If a sarcoma is diagnosed, further tests may be done on the sample to try to find out exactly what type of sarcoma it is.

Waiting for test results can be an anxious time for you. It may help to talk about your worries with a relative or friend. You could also speak to one of our cancer support specialists on 0808 808 00 00.

Grading and staging of leiomyosarcoma


Grading refers to the appearance of cancer cells under a microscope. The grade gives an idea of how quickly a cancer may develop.

Grading of soft tissue sarcomas can sometimes be difficult, especially for the less common types.

Low-grade means that the cancer cells look very much like the normal cells of the soft tissues. They are usually slow-growing and are less likely to spread. In high-grade tumours the cells look very abnormal, are likely to grow more quickly, and are more likely to spread.


The stage of a cancer is a term used to describe its size and whether it has spread beyond its original site. Knowing the particular type and the stage of the cancer helps the doctors decide on the most appropriate treatment.

The following is a commonly used staging system for non-gynaecological leiomyosarcoma. A different system is used for leiomyosarcoma arising in the gynaecological organs (the organs of the female reproductive system). Your specialist can explain more if you have this type of leiomyosarcoma.

Stage 1A

The tumour is low-grade and small (less than 5cm [2in]). It can be near the surface of the body (superficial) or deep within the body, but with no sign that it has spread to the lymph nodes or other parts of the body.

Stage 1B

The tumour is low-grade and large (more than 5cm [2in]). It’s superficial with no sign that it has spread to the lymph nodes or other parts of the body.

Stage 2A

The tumour is low-grade and large (more than 5cm [2in]). It’s deep within the body but has not spread to the lymph nodes or other parts of the body.

Stage 2B

The tumour is high-grade and small (less than 5cm [2in]). It can be near the surface of the body or deep within the body, but has not spread to the lymph nodes or other parts of the body.

Stage 2C

The tumour is high-grade, large (more than 5cm [2in]) and superficial, but has not spread to the lymph nodes or other parts of the body.

Stage 3

The tumour is high-grade, large (more than 5cm [2in]) and deep, but has not spread to the lymph nodes or other parts of the body.

Stage 4

The tumour has spread to lymph nodes in the area or to any other part of the body. This is known as secondary or metastatic soft tissue sarcoma.

Recurrence of leiomyosarcoma

This means that a soft tissue sarcoma has come back after it was first treated. It may come back in the tissues where it first started (local recurrence) or in another part of the body (metastasis).

Treatment for leiomyosarcoma

As sarcomas are rare, they are usually treated by a team of doctors and other health care professionals at a specialist hospital. This means that you may have to travel some distance to have your treatment.

The treatment for leiomyosarcoma depends on a number of things, including your general health and the size and position of the tumour in the body. The results of your tests will help your doctor plan the best type of treatment for you. They will then discuss this with you.

The usual treatment for a leiomyosarcoma is surgery, wherever possible, to remove the tumour. This may be followed by radiotherapy to reduce the chance of the cancer coming back.

Chemotherapy is also used for some leiomyosarcomas. It’s mainly used to treat a leiomyosarcoma that has come back (recurred), or that has spread (advanced or metastatic cancer). Chemotherapy may also sometimes be used after surgery to try to reduce the chances of it coming back.

Treatment of sarcomas is discussed in more detail in our general information about soft tissue sarcomas.

Clinical trials

Research into treatments for leiomyosarcoma is ongoing and advances are being made. Cancer doctors use clinical trials to assess new treatments.

Before any trial is allowed to take place, it must be approved by an ethics committee, which protects the interests of the patients taking part.

You may be asked to take part in a clinical trial. If you decide to take part, your doctor will discuss the treatment with you so that you have a full understanding of the trial and what it means to take part. You may decide not to take part or withdraw from a trial at any stage. You’ll still receive the best standard treatment available.

Follow-up after treatment

After your treatment is completed, you will have regular check-ups and x-rays. Your specialist will advise you on how frequently you need to be seen. Follow-up will continue for several years. If you have any problems, or notice any new symptoms in between your regular appointments, let your doctor know as soon as possible.

Your feelings

You may have many different emotions, including anger, resentment, guilt, anxiety and fear. You may find yourself tearful, restless and unable to sleep. Or you may have feelings of hopelessness and depression. These are all normal reactions but it can be difficult and distressing to admit to them.

The need for support will vary from person to person and may depend on the treatment you receive and any side effects this causes. Your specialist will tell you about any potential side effects and how to deal with them before you begin any treatment.

Some hospitals have their own emotional support services with trained staff, and some of the nurses on the ward will have had training in counselling. You may feel more comfortable talking to a counsellor outside the hospital environment or to a member of your religious faith, if you are religious.

Everyone has their own way of coping with difficult situations. Some people find it helpful to talk to family or friends, while others prefer to keep their feelings to themselves. There is no right or wrong way to cope, but help is available if you need it. Our cancer support specialists can give you information and support to help you cope.

Some of these organisations can also help you cope with your feelings:

  • Sarcoma UK provides information and support to anyone affected by sarcoma.
    Tel 020 7250 8271
    Email info@sarcoma.org.uk
  • The Rarer Cancers Foundation provides guidance, information and support for people affected by rare types of cancer.
    Tel 0800 334 5551
    Email patientsupport@rarercancers.org.uk

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