Uterine fibroids are benign, or noncancerous, growths. Current evidence does not show that they turn into cancer. A rare cancer called uterine leiomyosarcoma can look like a fibroid, which is why unusual symptoms or imaging findings sometimes need more tests. Most people with fibroids do not have cancer. If you have bleeding after menopause, new pelvic symptoms, or questions about a uterine mass, talk with a qualified clinician.
Medical Disclaimer: This article is for educational and informational purposes only and is not medical advice. It cannot diagnose a uterine growth or determine which treatment is right for you. Consult your physician or another qualified healthcare professional before making medical decisions.
Hearing that you have a uterine tumor can be frightening, especially if no one has explained what the word means. If you’re asking, “Can fibroids be cancerous?” the short answer is that true uterine fibroids are benign. Still, some uncommon uterine conditions can look similar at first. Understanding the difference can help you prepare useful questions for your care team. Texas IR & Interventional Oncology provides information about fibroids and minimally invasive treatment options for eligible patients in the Houston area.
Are Uterine Fibroids Cancerous?
No. Uterine fibroids, also called leiomyomas or myomas, are growths of muscle and connective tissue that develop in or around the uterus. They are benign tumors, meaning they are not cancer. The word tumor simply means an abnormal growth; it does not always mean a malignant disease.
Fibroids are common during the years before menopause. They may be very small or large enough to cause pressure on nearby organs. Some people have one fibroid, while others have several. Many cause no symptoms. Clinicians may find them during a routine examination or an ultrasound for another concern.
According to the American College of Obstetricians and Gynecologists, fibroids can lead to heavy periods, pelvic discomfort, and bladder or bowel symptoms. Those problems deserve care, but they do not make a growth cancerous.
Can Fibroids Turn Into Cancer?
There is no convincing evidence that an ordinary benign fibroid turns into cancer. Fibroids also do not appear to increase a person’s risk of developing other forms of uterine cancer. This distinction matters because searching for “fibroid cancer” can make two different diagnoses sound like the same disease.
Very rarely, doctors discover cancer of the uterine muscle in someone whose growth initially appeared to be an ordinary fibroid. Doctors work to identify that possibility, but even a careful assessment cannot rule it out in every case before surgery.
What is uterine leiomyosarcoma?
Uterine leiomyosarcoma is a rare cancer that starts in the smooth muscle of the uterus. It is different from a benign leiomyoma. It is also different from endometrial cancer, which begins in the inner lining of the uterus. The National Cancer Institute explains these differences in its guidance on uterine sarcoma.
A leiomyosarcoma can resemble a fibroid because both may appear as a mass within the uterine wall. That possibility is uncommon, but it is one reason a clinician may recommend closer review when findings do not look typical.
What Are the Symptoms of Cancerous Fibroids?
“Cancerous fibroid” is a common search phrase, but it is not a precise medical diagnosis. The concern is whether a rare uterine cancer could be mistaken for a benign fibroid. Symptoms can overlap, so no single symptom can tell you which type of growth is present.
Common symptoms of benign uterine fibroids
Benign fibroids may cause heavy or long menstrual periods, cramps, pelvic pressure, a feeling of fullness, frequent urination, constipation, or pain during sex. Heavy bleeding can also lead to anemia, which may cause tiredness or weakness. Some fibroids cause no symptoms at all.
The size and location of a growth often affect how someone feels. A small fibroid near the uterine lining can cause troublesome bleeding, while a larger fibroid elsewhere may cause pressure rather than bleeding.
Warning signs that need medical evaluation
Speak with a healthcare professional about bleeding between periods, pelvic pain that persists, or symptoms that are new or changing. A clinician should evaluate any vaginal bleeding after menopause, even if you have a history of fibroids. The National Cancer Institute’s uterine sarcoma guidance lists unusual bleeding, pain, and fullness among symptoms that may need investigation.
These signs do not mean you have cancer. Many noncancerous conditions can cause them. Seek prompt medical care if you have very heavy bleeding, faintness, or sudden severe pelvic pain.
Can You Tell the Difference Between Fibroids and Cancer on an Ultrasound?
Clinicians often start with an ultrasound when they suspect fibroids. It shows the uterus and helps clinicians measure and locate growths. But an ultrasound image alone cannot always confirm that an unusual uterine mass is benign.
What can an ultrasound show?
During a pelvic or transvaginal ultrasound, sound waves create pictures of the uterus. Clinicians look at the number, size, position, and appearance of growths. Ultrasound also helps them assess other causes of pelvic symptoms.
Clinicians can often manage a typical-looking fibroid without surgery. If a mass looks unusual, the clinician may recommend further imaging or a gynecology referral rather than making assumptions based on one image.
When are MRI or additional tests needed?
Magnetic resonance imaging (MRI) can show more detail about the uterine wall and a mass’s features. It can help clinicians plan treatment and identify findings that require further evaluation. However, neither ultrasound nor MRI can reliably rule out every leiomyosarcoma.
A clinician may recommend sampling the uterine lining for certain bleeding concerns, particularly after menopause. That test helps evaluate the lining of the uterus, but it may miss a cancer arising deeper in the muscle. The care team chooses tests based on symptoms, age, imaging, and medical history.
What Percentage of Fibroids Are Cancerous?
True uterine fibroids are benign by definition, so there is no useful percentage of ordinary fibroids that are “cancerous.” A more accurate question is: how often do doctors unexpectedly find uterine cancer during surgery for what appeared to be a fibroid?
In its guidance on uterine surgery, ACOG reports a wide estimated range: from about 1 unexpected leiomyosarcoma in 770 surgeries to fewer than 1 in 10,000 surgeries for presumed symptomatic fibroids. Those figures describe selected surgical patients, not all people with fibroids. They cannot tell you your personal cancer risk.
The practical takeaway is that leiomyosarcoma is rare. Your symptoms, imaging, age, and clinical history matter more for deciding which follow-up steps make sense than applying a broad percentage to yourself.
Can Fibroids Be Cancerous After Menopause?
A fibroid does not become cancerous simply because menopause occurs. In fact, fibroids often shrink after menopause as estrogen and progesterone levels fall. Some may remain or change in size, so an existing fibroid is not automatically a cause for concern.
However, do not dismiss new bleeding after menopause as a normal fibroid symptom. A clinician may need to look for causes involving the uterine lining, cervix, or another pelvic condition. Depending on the circumstances, clinicians may also need to assess a newly discovered or changing uterine mass.
If you have passed menopause and notice spotting, bleeding, or ongoing pelvic changes, make an appointment with your gynecologist. A proper evaluation is more useful than trying to determine cancer risk from the size of a fibroid alone.
How Do Doctors Diagnose a Suspicious Uterine Growth?
The first step is a careful review of your symptoms and medical history. Your clinician may ask when bleeding began, whether you have gone through menopause, how your symptoms have changed, and which treatments or scans you have already had.
A pelvic examination and ultrasound can help identify the source of symptoms. MRI may provide additional detail if an ultrasound is unclear or a clinician is planning treatment. Blood tests can check for anemia when heavy bleeding is a concern, but they cannot reliably identify leiomyosarcoma in a uterine muscle mass.
For abnormal bleeding, a clinician may recommend sampling the endometrial lining. That can help detect some cancers of the lining, but it does not reliably exclude leiomyosarcoma within the uterine muscle. As ACOG explains in its clinical guidance, clinicians generally cannot diagnose leiomyosarcoma reliably before surgery; a pathologist often needs to examine tissue to make a final diagnosis.
If findings raise concern for cancer, your care team may involve a gynecologic oncology specialist before deciding on treatment. That referral is a precaution based on the findings, not a diagnosis by itself.
What Happens If Your Fibroids Are Benign?
Not every fibroid needs treatment. If a fibroid causes no problems, your clinician may recommend monitoring it. When fibroids cause heavy periods, pelvic pressure, or other symptoms, treatment depends on your goals, the size and location of the fibroids, your age, and whether future pregnancy matters to you.
Options may include medication to manage bleeding, myomectomy to remove fibroids while leaving the uterus in place, hysterectomy to remove the uterus, or an image-guided procedure for suitable patients. There is no single best choice for everyone.
When is uterine fibroid embolization an option?
Uterine fibroid embolization (UFE) is a minimally invasive option for some people with symptomatic benign fibroids. An interventional radiologist guides a small catheter into blood vessels supplying the fibroids and delivers tiny particles that reduce their blood flow. Over time, the fibroids may shrink.
UFE does not treat uterine cancer. A known or suspected gynecologic malignancy requires a different evaluation and care plan. As ACOG notes in its patient guide to uterine artery embolization, patients should discuss the procedure’s benefits, risks, and effect on future pregnancy with their clinicians. Fibroid evaluation and suitable imaging come before deciding whether UFE is appropriate.
When to Seek a Fibroid Evaluation in Houston and Katy
If a clinician has diagnosed fibroids but you are unsure what your test results mean, begin by discussing them with your gynecologist. Ask whether the imaging looks typical for benign fibroids, whether bleeding needs additional testing, and which options fit your symptoms and plans.
If your clinician has diagnosed benign fibroids and you want to explore minimally invasive treatment, Dr. Poyan Rafiei and the team at Texas IR discuss UFE candidacy at their Katy office, serving patients in the greater Houston area. You can also find Texas IR’s Google Business Profile for office information. If your care team suspects cancer, you need an appropriate gynecologic or oncology evaluation first.
Frequently Asked Questions
- What are the worst symptoms of fibroids? – Very heavy bleeding, severe pelvic pain, and pressure that affects urination can disrupt daily life and warrant medical attention. Heavy blood loss can cause anemia. Seek urgent care for severe bleeding, fainting, or sudden intense pain.
- Which size of fibroid is dangerous? – There is no single size that means a fibroid is cancerous or dangerous. Location and symptoms matter, and even smaller fibroids can cause heavy bleeding. Your clinician can explain whether a particular growth needs monitoring or treatment.
- Can rapidly growing fibroids be cancerous? – Growth alone does not show whether a mass is cancerous. ACOG notes that rapid uterine growth is not a reliable predictor of leiomyosarcoma. Still, ask a clinician to evaluate a newly enlarging mass or changing symptoms.
- Do fibroids increase your risk of uterine cancer? – Having fibroids does not appear to raise your risk of uterine cancer. A rare uterine cancer may sometimes resemble a fibroid, which is a different issue from a benign fibroid becoming cancer.
- Can fibroids be removed without a hysterectomy? – Yes. Myomectomy removes fibroids while keeping the uterus. For suitable patients, UFE may shrink fibroids without removing the uterus. The best option depends on symptoms, fertility plans, imaging, and medical history.
Conclusion
If your symptoms make you worry about cancer, remember that fibroids are benign, even though rare uterine cancers can resemble them. Persistent symptoms or unusual bleeding deserve a thoughtful medical evaluation, not a self-diagnosis from an online search. If benign fibroids affect your daily life and you want to discuss treatment options in Katy or Houston, schedule a consultation with Texas IR to learn whether UFE may be appropriate after appropriate evaluation.
Medical Disclaimer: This article is for educational and informational purposes only and is not medical advice. It cannot diagnose a uterine growth or determine which treatment is right for you. Consult your physician or another qualified healthcare professional before making medical decisions.
References
- American College of Obstetricians and Gynecologists (ACOG). Uterine Fibroids. https://www.acog.org/womens-health/faqs/uterine-fibroids
- ACOG. Uterine Morcellation for Presumed Leiomyomas, Committee Opinion No. 822 (2021). https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2021/03/uterine-morcellation-for-presumed-leiomyomas
- National Cancer Institute. What Is Uterine Sarcoma? https://www.cancer.gov/types/uterine/sarcoma
- National Cancer Institute. Uterine Sarcoma Symptoms. https://www.cancer.gov/types/uterine/sarcoma/symptoms
- ACOG. Uterine Artery Embolization (UAE). https://www.acog.org/womens-health/faqs/uterine-artery-embolization
- Mayo Clinic. Uterine Fibroids: Symptoms and Causes (September 3, 2026). https://www.mayoclinic.org/diseases-conditions/uterine-fibroids/symptoms-causes/syc-20354288
- UT MD Anderson Cancer Center. Uterine Fibroids and Cancer: Is There a Connection? (August 1, 2024). https://www.mdanderson.org/cancerwise/uterine-fibroids-and-cancer–is-there-a-connection-.h00-159699912.html
- Japanese Society of Interventional Radiology. Uterine Artery Embolization for Symptomatic Uterine Myomas: Procedural Guidelines 2021, English version. https://pmc.ncbi.nlm.nih.gov/articles/PMC12460036/