Leiomyosarcoma

Written by Stephanie Watson, Danny Bonvissuto, Felicia Wilson
Medically Reviewed by Zilpah Sheikh, MD on March 05, 2025
7 min read

Leiomyosarcoma (LMS) is a rare cancer that starts in smooth muscles that line organs such as your stomach, bladder, and intestines.

These muscles are involuntary, meaning you can't control them. For example, they make your stomach contract to digest food.

You have smooth muscles all over your body, including in your:

  • Bladder
  • Blood vessels
  • Intestines
  • Liver
  • Pancreas
  • Skin
  • Stomach
  • Uterus

You can get leiomyosarcoma cancer in any of these organs. But it most commonly starts in the uterus, stomach, arms and legs, and small intestine.

LMS isn't the same as leiomyoma. Leiomyoma also starts in smooth muscles, but it's not cancer and doesn't spread.

Doctors don't know what causes LMS. It might result from gene changes that cause cells to grow out of control and form tumors. These changes can happen on their own or be passed down from one of your parents.

Most people who get this type of cancer are over 50. Some people get LMS years after they've had radiation for a different kind of cancer.

You also might be at risk if you've been exposed to certain chemicals, such as:

  • Dioxins, which are produced when companies make things such as pesticides and paper
  • Vinyl chloride, which is used to make plastic
  • Weedkillers

The signs of LMS depend on the size and location of the cancer. Some people have no symptoms.

LMS can cause these general cancer symptoms:

  • Bloating in your abdomen
  • Fatigue
  • Fever
  • Lump or swelling under your skin
  • Nausea and vomiting
  • Pain
  • Weight loss

LMS in your stomach or intestines can cause:

  • Stomachache
  • Black-colored stools
  • Vomiting blood

LMS in your uterus can cause:

  • Bleeding from your vagina that's not from a menstrual period
  • Discharge from your vagina
  • Need to pee more often than usual

Call your doctor if you notice any of these symptoms.

Your doctor will ask about your symptoms and medical history. You might need a biopsy to see if you have LMS. Your doctor will take a sample of tissue from the tumor using a needle or small cut. That sample goes to a lab, where it's tested to see if it's cancer. You also might have one or more of these tests to see where exactly the tumor is and how big it's grown:

  • CT scan: X-rays are taken from different angles and put together to show more information.
  • MRI: Powerful magnets and radio waves are used to make detailed pictures of organs and other parts of your body.
  • Ultrasound: Sound waves are used to make images of the inside of your body.

The results will help your doctor plan your treatment.

A leiomyosarcoma cancer diagnosis can bring up many questions. Make a list of everything you want to know. When you see your doctor, bring someone with you who can write down the answers while you listen.

Add your own questions to this list:

  • Has my cancer spread? If so, to what extent?
  • What stage is it? What does that mean?
  • What are my treatment options?
  • What are the side effects of those treatments?
  • Are there any other risks?
  • Which treatment do you suggest, and why?
  • Will I need to take medication? If so, which ones?
  • Do the medications have any side effects? 
  • What are the chances of leiomyosarcoma coming back after I have this treatment?
  • How can I prepare for treatment?
  • Tell me about your experience working with people who have leiomyosarcoma.
  • Should I get a second opinion?
  • What's my prognosis?

Your doctor will recommend a treatment based on:

  • Where the tumor is
  • Whether it has spread
  • How fast it's spreading
  • Your age and health

Surgery is the most common treatment for LMS. Your surgeon will take out the tumor and some of the tissue around it.

Women who have uterine cancer will need surgery to remove the uterus, and possibly the fallopian tubes and ovaries if the cancer has spread.

Other treatments for LMS include:

  • Radiation therapy: High-energy X-rays kill cancer cells or stop their growth. This is used to shrink the tumor before or after surgery.
  • Chemotherapy: Medicine is used to kill cancer cells. Your doctor might give you chemo if your cancer has spread or comes back after treatment. You might get a combination of two or more chemotherapy drugs.

After treatment, you'll see your doctor for regular checkups. If your cancer comes back, you'll be treated again with surgery, radiation, or chemotherapy.

Scientists are looking for new ways to treat leiomyosarcoma. Clinical trials are testing new drugs to see if they're safe and if they work. These trials are a way for people to try new medicines that aren't available to everyone. Your doctor can tell you if there's a clinical trial that might be a good fit for you.

Side effects of leiomyosarcoma treatments

If you choose chemotherapy, you may have some side effects including: 

  • Nausea
  • Vomiting
  • Hair loss 
  • Anemia
  • Weight loss 
  • Diarrhea
  • Constipation 
  • Fertility problems

If you try radiation therapy, you may have these side effects:

  • Pain or swelling in your legs, arms, or affected area
  • Skin dryness, itching or blistering
  • Pain or swelling at or around the tumor site
  • Fatigue

If you have surgery for leiomyosarcoma, you may have side effects such as: 

  • Nausea
  • Fatigue
  • Itchy skin

When you have leiomyosarcoma cancer, your days may be busy with treatments, appointments, and recovery. It can affect how you feel, both in general and about yourself.

Take good care of yourself. Everyone's version of self-care is different, but the basics include healthy eating, being physically active, getting enough sleep, connecting with people you enjoy, and managing your stress. These are positive habits for everyone, and you need them more than ever when you're dealing with any type of cancer. 

If your diagnosis starts to make you feel depressed or anxious, you may want to talk with a therapist experienced in working with people who have cancer or other serious illnesses. A support group may also be a good idea. Your oncologist's office should be able to refer you to those resources.

Self-care is also about things that bring you happiness. What made you feel your best before your diagnosis? Whether it's a hobby or a treat, make time for that.

Because leiomyosarcoma is an aggressive and rare cancer, survival rates are best if it's diagnosed early and contained to one part of your body.

If you look up survival rates for leiomyosarcoma cancer, you'll likely find information on soft tissue sarcomas. That's not very specific. Plus, survival rates are about big groups of people and can't predict what you can expect. Your best option is to ask your doctor about this.

Your doctor can figure out your prognosis based on your specific details. This includes your medical history, age, and current health, as well as the size, grade, and type of your tumor, how deep it is, and where it started.

The National Leiomyosarcoma Foundation has patient resources about diagnosis, treatment, research, and ways to get involved. Other cancer and sarcoma foundations that cover leiomyosarcoma include:

  • Leiomyosarcoma Support & Direct Research Foundation
  • The American Cancer Society
  • Genetic and Rare Diseases (GARD) Information Center
  • National Cancer Institute
  • Sarcoma Foundation of America
  • Sarcoma Alliance

Leiomyosarcoma (LMS) is a rare cancer that starts in smooth muscles, such as those in your stomach or intestines. It may happen due to gene changes. Risk factors include being over 50, past radiation therapy, and exposure to chemicals such as dioxins and vinyl chloride.

Symptoms such as fatigue, bloating, and pain can signal LMS, with more specific signs depending on where the tumor is. Diagnosis usually involves imaging tests (CT scans and MRIs) and a biopsy to confirm cancer.

Surgery is the main treatment for LMS, often followed by radiation or chemotherapy. Along with treatment, it's important to focus on self-care, like eating well, managing stress, and seeking emotional support from friends and family.

What are the odds of getting leiomyosarcoma?

Leiomyosarcoma is a very rare cancer. In the U.S., it accounts for about 1.4 cases per 100,000 people. It is more common in women than in men. While it can be diagnosed at any age, this type of cancer is common in people aged 50 or older.

What are the early symptoms of leiomyosarcoma?

You may not notice any signs at first. As the tumor grows, you may see signs of unexpected weight loss, nausea, pain during sex, unusual vagina bleeding or discharge, stomach or digestion problems, and bowel or bladder problems.

Does leiomyosarcoma run in families?

No. It does not run in families. However, it can be linked to some underlying genetic conditions, such as hereditary retinoblastoma, tuberous sclerosis, nevoid basal cell carcinoma syndrome, Gardner syndrome, and Werner syndrome.

Can you live a long life with leiomyosarcoma?

There is no exact estimate on how long you can live with leiomyosarcoma. It depends on the size and location of the tumor, whether it has spread, and if it can be or has been removed. If the tumor is caught early and fully removed, you are more likely to be cured. However, if it is discovered in the later stages, your treatment can be more complicated.

What is the treatment for uterine leiomyosarcoma?

Treatment for uterine leiomyosarcoma includes surgery to remove the entire uterus. It can also include removing the fallopian tubes and ovaries. In some cases, your lymph nodes could be removed as well. Other treatment options include radiation, chemotherapy, hormone therapy, or immunotherapy if the cancer is more advanced.

Can leiomyoma become leiomyosarcoma?

Yes. It is very rare, but a leiomyoma or uterine fibroid can become leiomyosarcoma. Researchers say it has happened in women who were postmenopausal and had large, fast-growing myomas (benign tumors).

Why is leiomyosarcoma so deadly?

Leiomyosarcoma is deadly because it is a very aggressive cancer. A tumor can double in size in as little as one month and spread quickly to other parts of your body. Once LMS tumors have spread, the treatment is more difficult. That's why identifying it early is crucial.