Leiomyosarcoma Symptoms & Causes


Here at Children’s Hospital Boston, we specialize in innovative, family-centered care. From your first visit, you’ll work with a team of professionals who are committed to supporting all of your family’s physical and psychosocial needs. We understand that you probably want to learn all you can about your child’s leiomyosarcoma to determine your next steps.  

What is leiomyosarcoma?

Leiomyosarcoma is a cancer of the muscle, particularly of soft tissue. It is a type of soft tissue sarcoma, and can appear in many places in the body, but in children it usually occurs in the gastrointestinal tract, which includes the stomach, small intestines, colon, appendix, rectum and anus. It can spread (metasize) to other areas of the body if it’s not removed, but if it is completely removed, it almost never reappear in other parts of the body. Overall, it is not a highly aggressive form of cancer and usually is not considered life threatening if it is treated early.

What are the different kinds of leiomyosarcoma?

  • soft tissue leiomyosarcoma
    • In children, soft tissue leiomyosarcoma is usually found in the gastrointestinal tract, which includes the stomach, small intestines, colon, appendix, rectum and anus.
    • Symptoms include abdominal discomfort and weight loss.
  • cutaneous (skin) leiomyosarcoma
    • Men are twice as likely to develop cutaneous leiomyosarcoma. In children, the risk is equal among girls and boys.
    • Surface level cutaneous leiomyosarcoma is usually benign, and usually does not move to other parts of the body (metastasize).
    • Small purple or red spots (lesions) deeper in the skin
  • vascular leiomyosarcoma
    • originating from major blood vessels
    • very rare condition
    • only a few hundred cases reported, ever
    • occurs in:
      • larger veins
      • vena cava
        • Veins that carry “old” blood that lacks oxygen (deoxygenated blood) from the body to the heart to be pumped through and regain oxygen.
        • Tumors in the vena cava cause Budd-Chiari syndrome, which leads to:
          • blockage of the vein (occlusion)
          • abdominal pain
          • accumulated abdominal fluid (acites)
          • enlarged liver (hepatomegaly)
          • yellow discoloring of the skin (jaundice)
      • pulmonary artery
        • shortness of breath, chest discomfort
  • immunocompromised host leiomyosarcoma
    • HIV, AIDS and the Eptstein-Barr virus (“mono”) compromises the immune system and can make your child more vulnerable to leiomyosarcoma.
  • bone leiomyosarcoma
    • extremely rare
      • only 90 cases reported since 1965
    • occurs in the metaphysis of long bones, where epiphyseal plates (“growth plates”) are
      • “Growth” plates start as cartilage and become bone (ossifies) when the child has stopped growing.
    • tumors in the long bones hard to find, as they appear translucent in radiographic testing (x-rays)

Is leiomyosarcoma common?

No, they are rare. As a group, soft tissue sarcomas (other than rhabdomysarcoma, which is slightly more common) account for less than 1 percent of all new cancer cases each year and 3 percent of all childhood tumors. More specifically:

  • Leiomyosarcoma accounts for 7 to 11 percent of all soft tissue sarcomas among adults and children.
  • In children, leiomyosarcoma is the most commonly found in the gastrointestinal tract.

Will my child be OK?

Leiomyosarcoma is extremely rare, and there are no official numbers on how well children manage the disease in the long term. However, doctors have studied soft tissue sarcomas (which is the category of cancer that and find that leiomyosarcoma falls under) and find that if a soft tissue sarcoma is completely resected, or removed, the survival rate is 80 percent or greater.  

Is it curable?

Yes. If the tumor is recognized and removed early enough before it grows too large, it can be resected and removed before it metastasizes, or moves to other regions of the body.

Symptoms and Causes

What are the symptoms of leiomyosarcoma?

Because soft tissue sarcomas affect tissue that is elastic and easily moved, a tumor may exist for a long time before being discovered, growing large and pushing aside surrounding tissue. Symptoms vary greatly with the size, location and spread of the tumor, but may include:

  • painless swelling or mass anywhere on the body
  • pain or soreness caused by compressed nerves or muscles
  • limping or other difficulty using the legs, feet, arms or hands

When are symptoms noticed?

If a child has leiomyosarcoma, usually the symptoms do not appear until adolescence, since it usually occurs in adults.

What causes leiomyosarcoma?

The exact cause of leiomyosarcoma is not entirely understood. However, studies have indicated that genetics may play a role in the formation of all soft tissue sarcomas. In addition:

  • Researchers have studied a small number of families that contain several members of one generation who have developed soft tissue sarcomas.
  • Limited studies have shown a possible link between soft tissue sarcomas and the development of other types of cancer.
  • Some inherited diseases have also been linked with an increased risk of developing soft tissue sarcomas.
  • There seems to be a link between leiomyosarcoma and Epstein-Barr virus infection.
  • Children with AIDS and those who are undergoing immunosuppression therapy for solid organ transplantation are also at increased risk for developing leiomyosarcoma.
  • Children with other forms of cancer, such as retinoblastoma, may be at higher risk for developing leiomyosarcoma as adults.

Questions to ask your doctor

After your child is diagnosed with leiomyosarcoma, you may feel overwhelmed with information. It can be easy to lose track of the questions that occur to you.

Lots of parents find it helpful to jot down questions as they arise- that way, when you talk to your child’s doctors you can be sure that all of your questions are concerned. If your child is old enough, you may want to suggest that he writes down what he wants to ask her health care provider too.

Here are some questions to get you started:

  • What can I do to help my child get ready for surgery?
  • Are there any particular foods or drink my child should avoid?
  • Could any of the current medications my child is taking affect her condition?
  • What are some ways I can address my child’s fear of surgery, chemotherapy or radiation?
  • How will I know if the tumor is completely removed?
  • How can I help my child recover after surgery?
  • When will my child be able to resume normal physical activity?
  • How could treatment affect my child’s academic and social life?
    Glossary of useful terms

    Have questions about some of the terms mentioned on the page? Visit our Cancer Care Glossary for more information.