Fibroids or Cancer? How Doctors Tell the Difference

In 2024, a young beauty influencer died from cervical cancer, though her symptoms had originally been diagnosed as fibroids. Her death brought a common concern and a difficult question into public discussion. She had reportedly lived for years with pelvic pain, fatigue and abnormal bleeding that had been attributed to fibroids after she was hospitalised; her death left women wondering whether cancer could be misdiagnosed as fibroids or whether a fibroid itself could eventually become malignant. These are understandable concerns and very prevalent among women. Other than excessive vaginal bleeding, early cervical cancer really has no other symptoms, and excessive bleeding is also a symptom of uterine fibroids.

A diagnosis of uterine fibroids can raise fears about cancer, particularly when symptoms persist or a fibroid appears to grow. In a 2017 German study of 807 women with fibroids, concern about malignancy was among the most commonly reported, alongside blood loss, treatment-related complications and the possibility of needing a hysterectomy. The same study found that better patient education reduced fears about malignant transformation; understanding what fibroids are, and what they are not, can therefore make an important difference to how patients approach treatment.

The distinction is especially important before a procedure such as uterine fibroid embolization (UFE). UFE is a treatment for benign uterine fibroids, so doctors need reasonable confidence that the mass being treated is in fact a fibroid. But not every woman with fibroids undergoes an extensive cancer workup. So how do doctors tell the difference?

Fibroids are tumours, but that does not mean they are cancer

The word tumour can be alarming because it is often used interchangeably with cancer in everyday conversation. Medically, however, the two terms are not synonymous.

A tumour is simply an abnormal mass of tissue. Fibroids, also called leiomyomas, are benign tumours arising from the smooth muscle and connective tissue of the uterus. They generally grow locally and they do not invade surrounding organs or metastasize to distant parts of the body. They are also extremely common. Many women have fibroids without knowing it because they cause no symptoms and may never require treatment. Prevalence increases with age, and studies from India have reported particularly high rates among women presenting with symptomatic gynaecological conditions.

So when a scan reports a “uterine tumour”, the word itself does not indicate malignancy. In the case of a typical fibroid, it describes a benign growth of uterine tissue.

Can a fibroid turn into cancer?

This is one of the most important misconceptions to address.

A benign fibroid does not gradually transform into a cancer simply because it has been present for many years, becomes large or is left untreated. The cancer most often confused with a fibroid is leiomyosarcoma (LMS), a malignant tumour that also arises from smooth muscle.

The important distinction is that leiomyosarcoma is considered a biologically different disease. It does not represent the usual progression of an established benign fibroid into cancer.

Why do the symptoms still cause confusion?

Fibroids and some gynaecological cancers can produce similar symptoms.

Fibroids commonly cause heavy or prolonged menstrual bleeding, pelvic pressure, abdominal enlargement and pelvic pain. But abnormal bleeding and pelvic pain are not exclusive to fibroids; they can also occur with cervical cancer, endometrial cancer, adenomyosis, endometrial polyps and other gynaecological conditions.

The conditions themselves are different. Cervical cancer develops in the cervix, whereas fibroids develop from the smooth muscle of the uterus.

Doctors do not diagnose a fibroid from symptoms alone. Symptoms provide an important starting point, but the diagnosis needs to be supported by clinical assessment and appropriate imaging. Depending on the circumstances, additional investigations may be needed.

Does a rapidly growing fibroid mean cancer?

Rapid growth is one of the findings that understandably makes patients anxious, but growth rate on its own cannot reliably distinguish a benign fibroid from a malignant mass. Fibroids can grow relatively quickly, particularly during periods of hormonal change such as pregnancy or during the reproductive years.

The context matters more than the speed alone. Doctors consider the patient's age, menopausal status, symptoms, previous imaging and the characteristics of the mass on imaging. A mass that continues to enlarge after menopause may warrant closer assessment because fibroids commonly become smaller when ovarian hormone levels decline. By contrast, growth during the reproductive years is not, by itself, evidence of malignancy.

How doctors investigate a fibroid when there is uncertainty

There is no single test that can identify every uterine sarcoma before treatment. Instead, doctors bring together several pieces of information.

Ultrasound is usually the starting point. It can establish the size and location of a uterine mass and often shows the characteristic appearance of a fibroid. In many patients, this is all that is required for an initial diagnosis.

Sometimes, however, the findings are less typical. For example, if the borders appear irregular, or the internal structure unusual, or in case of difficulties determining exactly what type of mass is present, an MRI can provide a much more detailed assessment of the uterus and the internal architecture of the lesion.

MRI is particularly useful because fibroids can undergo degeneration. Degenerating fibroids can develop internal changes that look different from a typical fibroid and may sometimes resemble more concerning pathology. MRI can help doctors interpret these findings in context.

Even so, MRI is not infallible. Imaging cannot exclude leiomyosarcoma with absolute certainty in every case; clinical history and other findings still matter.

What role do blood tests play in selected cases?

When imaging leaves a genuine diagnostic question, doctors may consider certain serum biomarkers as part of the evaluation.

One of these is LDH, or lactate dehydrogenase. LDH may be elevated in leiomyosarcoma compared with benign fibroids and is among the more established biomarkers investigated in this setting.

CA-125 may also be elevated in some uterine sarcomas. However, it is not specific for cancer; benign conditions, including fibroids and endometriosis, can also increase CA-125 levels. This limits its usefulness as a standalone test.

Another marker that has been studied is HE4, or human epididymis protein 4. Research has examined HE4 in combination with LDH and CA-125, with the combination showing greater diagnostic value in some studies than individual markers alone.

These are not routine cancer-screening blood tests for every woman with fibroids. Most patients with fibroids will never need them as they are considered mostly when imaging is equivocal or when other clinical factors make further investigation appropriate.

When is a biopsy considered?

If uncertainty remains after imaging and, where appropriate, blood tests, tissue sampling may be considered.

A biopsy can provide microscopic information about the cells within a lesion; specialised techniques have also been studied for improving the identification of malignant pathology. Biopsy-based approaches report high diagnostic accuracy in selected settings.

What findings make doctors investigate further?

Doctors become more cautious when several features occur together rather than because of one isolated finding.

These may include rapid growth accompanied by other atypical features, continued growth after menopause, imaging characteristics that do not fit a typical fibroid, or a symptom pattern that does not correspond well with the expected presentation.

When such findings are present, further evaluation may involve additional imaging, blood tests, closer surveillance, biopsy or referral to a gynaecological oncologist.

Why diagnosis matters before Uterine Fibroid Embolization (UFE)

UFE is intended to treat benign uterine fibroids. The decision to proceed therefore begins with establishing that the uterine mass has been reasonably characterised as a fibroid.

Once that has been established, candidacy for UFE depends on several other factors. The location, size and number of fibroids matter because different fibroid configurations may respond differently to embolization. The symptoms also matter: heavy menstrual bleeding, pelvic pressure and bulk-related symptoms can influence the treatment discussion.

What happens after the evaluation?

For most women, the evaluation confirms that the uterine masses are benign fibroids. At that point, the discussion moves away from the fear of cancer and toward the question of which treatment, if any, is appropriate for this patient?

Depending on symptoms and individual circumstances, options may include observation, medication, UFE, myomectomy or other minimally invasive approaches.

If the assessment instead identifies features that are genuinely concerning, the pathway changes. Further MRI assessment, selected biomarkers such as LDH, CA-125 and HE4, biopsy or referral to a gynaecological oncologist may be appropriate.

The key point, as we established, is that these are different diseases. The word “tumour” does not automatically mean cancer. Fibroids are benign uterine tumours, and an established fibroid does not simply transform into leiomyosarcoma because it grows or remains untreated.

What doctors account for is the small possibility that a mass thought to be a fibroid may actually represent a different condition. That is why the clinical picture considers symptoms, imaging, growth pattern, age and menopausal status, with additional investigations used when the findings warrant them.

The distinction also matters before UFE. UFE is a treatment for benign fibroids, so the mass should be appropriately characterised before embolization is undertaken.

If the diagnosis is clear and the findings are typical, the discussion can move on to whether treatment is needed and which option best fits the patient’s symptoms, fertility plans and preferences. If something does not fit the usual pattern, that uncertainty deserves to be investigated before any procedure is chosen.

Why choose RIVEA for UFE?

At RIVEA, UFE begins with accurate diagnosis and careful patient selection. Our interventional radiology team evaluates the size, number, location and vascularity of fibroids to determine whether UFE is appropriate for you. When required, advanced imaging helps establish a clear treatment plan, while our multidisciplinary expertise allows other treatment options to be considered when UFE may not be the best choice.

The procedure is performed using image-guided techniques designed to precisely target the blood supply to the fibroids, while preserving the uterus. From evaluation through recovery, care is planned around your symptoms, clinical findings and individual treatment goals.