Leiomyosarcoma: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Leiomyosarcoma?
Leiomyosarcoma is usually treated by a team led by a medical oncologist (a cancer doctor who uses medicine), a surgical oncologist (a cancer surgeon), and a radiation oncologist (a doctor who treats cancer with radiation). A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is leiomyosarcoma?
Leiomyosarcoma is a cancer that starts in smooth muscle cells. Smooth muscles are muscles you do not control on purpose. They help move food through the digestive tract, for example. It is a type of soft tissue sarcoma, a cancer of the body's connective tissue.
Smooth muscle is found all over the body, so the tumor can form almost anywhere. The uterus is the most common place. Sarcomas are rare. They make up less than 2% of all cancer diagnoses.
Symptoms
Symptoms depend on where the tumor is, how big it is, and whether it has spread. Early on, it may cause no obvious symptoms. Signs can include:
- A lump or swelling. A soft tissue sarcoma may appear as a painless lump under the skin, often on an arm or a leg.
- Trouble breathing or pain, when a growing soft tissue sarcoma presses on nearby organs, nerves, muscles, or blood vessels.
- Tiredness, fever, weight loss, and nausea and vomiting.
- Bleeding in the digestive tract, which can cause black, tarry, foul-smelling stools.
- In the uterus, abnormal bleeding from the vagina, unusual discharge, and a change in bladder or bowel habits.
Pain may occur in the affected area but is uncommon. Most forms are aggressive and may spread to places such as the lungs or liver.
Causes and who gets it
The exact cause is unknown. Cancers start when genes that control how cells grow and divide change. These changes can happen on their own for unknown reasons or, more rarely, can be inherited.
NCI lists some risk factors for soft tissue sarcomas in general. They include certain inherited disorders, past radiation therapy, long-term lymphedema (swelling from fluid buildup) in an arm or leg, and contact with certain chemicals such as vinyl chloride. Leiomyosarcoma affects both males and females.
How doctors diagnose it
Doctors start with your history and an exam. They may order blood tests and imaging tests such as CT, MRI, or ultrasound. These show the size and place of the tumor. A biopsy, where a small sample of tissue is removed and checked under a microscope, confirms the diagnosis. A key step is telling cancer apart from a leiomyoma, a non-cancer tumor of smooth muscle.
Treatment
Care may need a team of cancer specialists. The main treatment is surgery to remove the whole tumor and the tissue around it. After surgery, radiation therapy may be added. If surgery is not possible because of where the tumor is or how far it has spread, radiation may be used alone.
Chemotherapy (cancer-fighting medicine) may be recommended for cancer that has grown into nearby areas, spread, or come back. A 2024 NCI report says adding trabectedin (Yondelis) to doxorubicin as first treatment helped people with advanced leiomyosarcoma live longer than doxorubicin alone. It also caused more serious side effects, such as low blood cell counts and temporary liver damage. Choices depend on your health and what matters to you.
When to see a doctor
Check with your doctor about a new lump or swelling, pain, or trouble breathing. Also check in about black, tarry stools or unusual vaginal bleeding. Other conditions can cause the same signs, so tests are needed.
Call 911 or go to the emergency room if you vomit blood, have severe trouble breathing, or have bleeding that will not stop.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Such a doctor can examine a new lump, order first tests, and refer you to a cancer team. They can also help with follow-up and coordinate your care.
Common questions
Is leiomyosarcoma a cancer?
Yes, leiomyosarcoma is a cancer. It is a malignant tumor that starts in smooth muscle cells. It is a type of soft tissue sarcoma.
Where in the body can leiomyosarcoma start?
It can start almost anywhere there is smooth muscle. NORD lists blood vessels, the digestive tract, the uterus, and the skin. The uterus is the most common place.
Is leiomyosarcoma the same as a leiomyoma?
No, they are different. A leiomyoma is a benign (non-cancer) smooth muscle tumor, while leiomyosarcoma is cancer. A biopsy helps doctors tell them apart.
What is the main treatment for leiomyosarcoma?
Surgery to remove the whole tumor and the tissue around it is the main treatment. Radiation therapy or chemotherapy may be added, depending on the tumor and your health.
Can leiomyosarcoma come back?
Yes, it can. NORD says leiomyosarcoma has a high risk of coming back after treatment if it is not diagnosed early.
Sources
- National Organization for Rare Disorders - Leiomyosarcoma
- National Cancer Institute - Trabectedin and Doxorubicin Effective for Leiomyosarcoma
- National Cancer Institute - Soft Tissue Sarcoma Treatment (PDQ)
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
