Definition

Leiomyosarcoma is a rare type of soft tissue cancer. This cancer starts in cells that make up smooth muscle which can be found throughout the body. These muscles control involuntary movement of organs, blood vessels, and skin.

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

Female Reproductive System

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Causes

Cancer occurs when cells in the body divide without control or order. Eventually these uncontrolled cells form a growth or tumor. These growths are malignant which means they can invade nearby tissues including the lymph nodes. Cancer that has invaded the lymph nodes can then spread to other parts of the body.

Cancer growth occurs when there are problems in the DNA of cells. It is not clear exactly what causes these problems, but is probably a combination of genetics and environmental factors.

Risk Factors

Some genetic disorders are associated with an increased risk of leiomyosarcoma. Examples include:

• Retinoblastoma —a rare type of cancer that affects the retina of the eye
• Familial adenomatous polyposis—abnormal growth of adenomatous polyps in the colon and/or rectum that can transform into cancer
• Neurofibromatosis type 1
• Li-Fraumeni syndrome
• Werner syndrome
• Nevoid basal cell carcinoma syndrome (Gorlin syndrome)

Other factors that may increase the chance of leiomyosarcoma include:

• Past history of cancer treatment with radiation therapy or tamoxifen
• Exposure to certain chemicals used to make plastics or weed killers

Symptoms

Leiomyosarcoma usually does not have symptoms. If present, symptoms will vary depending on the tumor’s location, size, and growth. As the tumor grows, it presses on nearby structures, causing problems. When they appear, general symptoms may include:

• Swelling or a lump
• Abdominal bloating
• Abnormal vaginal bleeding
• Shortness of breath
• Pain
• Numbness or muscle weakness

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done. This includes a thorough examination of the affected area and blood tests.

Imaging tests can help diagnose and determine the extent of cancer. Tests may include:

• Ultrasound
• CT scan
• MRI scan
• PET scan

A biopsy will help tell the difference between a noncancerous or cancerous growth. A tissue sample from the affected area is examined under microscope for the presence of cancer cells.

The physical exam, combined with all of the test results, will help to determine the type, grade, and stage of cancer. Staging is used to guide a treatment plan. Leiomyosarcoma is staged from I-IV (1-4). Stage I is a cancer that has stayed in one area, while stage IV indicates a spread to other parts of the body. Cancer cells may also be graded by how fast they might grow and spread.

Treatment

Cancer treatment varies depending on the location, size, grade, and stage of the tumor, your age, and overall health. Since leiomyosarcoma is rare, treatment with a specialty team may be needed. A combination of treatments may be best.

Prevention

There are no current guidelines to prevent leiomyosarcoma because the cause is not clear.