Leiomyosarcoma is a rare condition. The cancer cells grow and multiply abnormally to form a tumor in the smooth muscle tissue of the body. Smooth muscle refers to the muscle tissue that lines hollow parts of the body, such as the bladder, uterus, stomach, veins, and arteries.

Leiomyosarcoma is a form of soft tissue sarcoma, which is a cancer that begins in the connective tissues of the body.

Where is leiomyosarcoma found?

Leiomyosarcoma often begins in the abdomen. The uterus is the most common location among women. See our comprehensive guide for more information about uterine sarcoma. Other parts of the body where leiomyosarcoma can form include the bladder, stomach, veins, and arteries.

What are the signs of leiomyosarcoma?

The signs of leiomyosarcoma vary depending on where the tumor is located. Unfortunately, most people do not experience symptoms until the tumor has grown quite large. For example, someone with leiomyosarcoma in the abdomen may experience weight gain in the stomach of up 10 to 20 pounds.

How is leiomyosarcoma diagnosed?

Doctors use imaging to detect leiomyosarcoma. These tests typically include MRIs or CTs. The scans can show the size of the tumor, where it started, whether any nearby organs or tissues are involved, and whether the tumor has spread to other parts of the body.

Biopsy is usually the next step. A biopsy is the only test that can make a definite diagnosis of leiomyosarcoma. It involves taking a sample of the tumor. That sample is checked under a microscope for cancer cells by a pathologist (a doctor who is specially trained to diagnose disease).

It is very important to receive a diagnosis from a team of doctors that is highly experienced in the diagnosis and treatment of soft tissue sarcoma. There are more than 80 subtypes of soft tissue sarcoma, so it can be a difficult to diagnose. Getting the correct evaluation and diagnosis is the first step to being cured.

What are the treatments for leiomyosarcoma?

The main treatment for leiomyosarcoma is surgery to remove the tumor. Leiomyosarcoma can begin in many different parts of the body. The surgery that’s right for you depends on the exact size and location of the tumor.

Some people may be able to have a minimally invasive operation. This includes laparoscopic (minimal incision) surgery. At Memorial Sloan Kettering, our soft tissue sarcoma surgeons are highly skilled in these techniques. We have a lot of experience in figuring out if such an approach might be right for you.

Oftentimes a traditional operation, also called an open operation, is required to remove the tumor completely. This is especially common for large tumors or tumors that involve nearby organs or tissues. The key consideration is always which technique is best for curing the cancer and giving you the best quality of life afterward.

Radiation and chemotherapy are less beneficial for people with leiomyosarcoma than they are for people with other forms of soft tissue sarcoma. Some people with leiomyosarcoma that has spread to other parts of the body may benefit from chemotherapy. If an operation is successful, often no extra treatment is necessary.