Leiomyosarcoma is a rare type of cancer that begins in smooth muscle tissue. Smooth muscle tissue is found in many areas of the body, such as the digestive system, urinary system, blood vessels and uterus.

Leiomyosarcoma most often begins in the abdomen or uterus. It starts as a growth of abnormal cells and often grows quickly to invade and destroy normal body tissue.

Signs and symptoms of leiomyosarcoma depend on where the cancer starts. They might include pain, weight loss, and a growing lump or swelling that can be felt through the skin.

Leiomyosarcoma is a type of soft tissue sarcoma, which is a broad category of cancers that begin in the tissues that connect, support and surround other body structures.


Tests and procedures used to diagnose leiomyosarcoma depend on where the cancer occurs, but may include:

  • Physical exam. Your doctor may examine you to gather more clues about what's causing any signs and symptoms you may be experiencing.
  • Imaging tests. Imaging tests might include MRI, CT and positron emission tomography (PET).
  • Removing a sample of tissue for testing (biopsy). A biopsy procedure involves removing a sample of suspicious tissue for testing. The sample is sent to a lab where it's analyzed to see if it's leiomyosarcoma.

    How the biopsy sample is collected depends on where the suspicious tissue is located. The procedure requires careful planning so that the biopsy is done in a way that won't interfere with future surgery to remove the cancer. For this reason, ask your doctor for a referral to a team of experts with experience in treating leiomyosarcoma.


Which treatments are likely to be most effective for you depend on the location and size of your leiomyosarcoma, as well as whether it has spread to other areas of your body. Your doctor also considers your overall health and your preferences when creating a treatment plan.

In general, treatments for leiomyosarcoma may include:

  • Surgery. The goal of surgery is to remove all of the leiomyosarcoma. But that might not be possible if the cancer has grown very large or has grown to involve other nearby organs. Instead, your surgeon may remove as much of the cancer as possible.
  • Radiation therapy. Radiation therapy uses powerful energy beams, such as X-rays and protons, to kill cancer cells. During a radiation therapy session, you lie on a table while a machine moves around you and directs the energy beams into your body. Radiation therapy might be recommended after surgery to kill any cancer cells that might remain.
  • Chemotherapy. Chemotherapy is a drug treatment that uses powerful chemicals to kill cancer cells. It might be recommended if the leiomyosarcoma can't be removed completely with surgery or if the cancer spreads to other areas of the body.
  • Targeted drug therapy. Targeted drug treatments focus on specific abnormalities present within cancer cells. By blocking these abnormalities, targeted drug treatments can cause cancer cells to die. Targeted drug therapy might be an option for advanced leiomyosarcoma. Your doctor may test your cancer cells to determine whether targeted drugs might be helpful for you.

Content From Mayo Clinic Updated: 12/06/2022
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