Definition

Leiomyosarcoma is a rare soft tissue cancer. The cancer cells start and grow in smooth muscle. Smooth muscle is found throughout the body. These muscles help organs, blood vessels, and skin to function.

Leiomyosarcoma can develop in any smooth muscle. It is most common in the muscle of the uterus, abdomen, and pelvis.

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Causes

Cancer happens when cells divide without control or order. These cells grow together to form a tumor. They can invade and damage nearby tissues. They can also spread to other parts of the body.

It is not clear what causes changes in the cells. It is likely a combination of genes and environment.

Risk Factors

Things that raise the risk of leiomyosarcoma are:

• Certain conditions, such as:
  • Retinoblastoma
  • Familial adenomatous polyposis
  • Neurofibromatosis type 1
  • Li-Fraumeni syndrome
  • Werner syndrome
  • Nevoid basal cell carcinoma syndrome (Gorlin syndrome)
• Past radiation treatment or use of tamoxifen
• Exposure to certain chemicals—in plastics or weed killers

Symptoms

There are often no symptoms. When symptoms occur, they vary depending on the site, size, and growth of the tumor. They may be:

• A swelling or lump
• Belly bloating
• Abnormal vaginal bleeding
• Problems breathing
• Pain
• Numbness or muscle weakness

Diagnosis

The doctor will ask about your symptoms and health history. A physical exam will be done. It will focus on the affected area.

Tests may include:

• Blood tests
• Imaging tests, such as:
  • Ultrasound
  • CT scan
  • MRI scan
  • PET scan
• A biopsy—a sample of tissue will be taken and tested

Imaging tests will help show where the cancer is and how far it has spread.

Biopsy will confirm the diagnosis. The exam and test results will be used for staging. This will outline how far and fast the cancer has spread.

Treatment

The goal is to remove the cancer. Treatment depends on the site, size, grade, and stage of the cancer. It also depends on the person's health and age. A combination of treatments may be used. Options may include:

• Surgery to remove:
  • The cancer and some nearby tissue
  • Lymph nodes in the area—if they are affected
  • Affected organs and structures—if needed
• External or internal radiation therapy—to kill cancer cells or shrink tumors
• Chemotherapy drugs by mouth, injection, or IV—to kill cancer cells

Prevention

There are no current guidelines to prevent leiomyosarcoma.