When Fibroids Grow to a Dangerous Size: Lessons From a Rare Case

By Dr. Jessie Wai Leng Phoon, MRCOG
Medical Director, GenPrime Fertility Singapore
Last reviewed: January 2026

Most people are told that uterine fibroids are common, benign, and slow growing. And in the vast majority of cases, that’s true.

But very rarely, fibroids can grow to an extraordinary size, placing significant strain on the body and turning what is usually a routine condition into a life-threatening surgical challenge.

This article explains what happens when fibroids become unusually large, how doctors distinguish benign fibroids from rare cancers, and why multidisciplinary care matters. It is based on a published BMJ case report describing the management of one of the largest uterine fibroids ever surgically removed from a living patient. 

BMJ case report large fibroid

How common are fibroids—and how rare are “giant” fibroids?

Uterine fibroids (leiomyomas) are the most common tumours of the female reproductive tract. By age 50, up to 70% of women will have fibroids at some point.

However, giant fibroids—generally defined as weighing more than 11 kg—are exceedingly rare today. With modern healthcare access and imaging, most fibroids are detected and treated long before they reach this size.

When fibroids do grow unchecked, they can:

• Compress surrounding organs
• Affect breathing and circulation
• Severely limit mobility
• Cause significant surgical risk

What happened in this rare case?

In the reported case:

• A 53-year-old postmenopausal woman presented with a massive abdominal swelling that had been enlarging over many years
• She developed breathlessness and difficulty lying flat, due to pressure on her lungs
• Imaging showed a huge uterine mass filling the abdomen and pelvis

The fibroid caused restrictive lung disease, meaning her lungs could not fully expand—an unusual but serious complication.

Why cancer had to be considered

When a uterine mass grows rapidly or reaches an extreme size—especially after menopause—doctors must consider uterine sarcoma, a rare but aggressive cancer.

In this case:

• The patient’s age
• The size of the mass
• Elevated blood markers

All raised concern for possible malignancy.

Doctors used a validated risk assessment tool (a preoperative sarcoma score) and planned surgery with intraoperative frozen section analysis, so that cancer could be identified immediately if present.

Fortunately, the mass was confirmed to be a benign fibroid, despite its size.

Why surgery was so complex

Removing a fibroid of this size is not routine surgery.

In this case:

• The fibroid weighed 27.8 kg—roughly the weight of a small child
• The mass was densely adherent to surrounding tissues
• Blood supply to the fibroid was extensive

During surgery:

• Blood loss reached 7 litres
• A massive transfusion protocol had to be activated
• The patient required intensive postoperative care

After removal, plastic surgeons were needed to reconstruct the abdominal wall, which had been stretched thin over many years.

What made this outcome possible?

This case highlights the importance of multidisciplinary care, involving:

• Gynaecologists and gynaecologic oncologists
• Anaesthetists experienced in high-risk surgery
• Plastic surgeons for abdominal reconstruction
• Intensive care and transfusion teams

Careful preoperative planning, intraoperative vigilance, and postoperative monitoring were critical to survival and recovery.

What this means for women with fibroids

While this case is extreme, it reinforces several important messages:

• Most fibroids are benign and slow growing
• Regular monitoring matters, especially if fibroids are enlarging
• New symptoms—such as breathlessness, rapid abdominal enlargement, or severe pressure effects—should not be ignored
• Rapid growth, particularly after menopause, warrants careful evaluation

Early detection and treatment almost always prevent fibroids from reaching this stage.

Fertility considerations

In women of reproductive age, fibroids can affect:

• Fertility
• Pregnancy outcomes
• Delivery planning

Surgical decisions should always take fertility goals into account. In contrast, for postmenopausal women or those who do not desire future fertility, hysterectomy may be the safest option—particularly when fibroids are large or symptomatic.

Questions to ask your doctor

If you’ve been diagnosed with fibroids, consider asking:

• How large are my fibroids, and are they growing?
• How often should they be monitored?
• Are there features that raise concern for something other than a benign fibroid?
• What symptoms should prompt urgent review?
• How might treatment affect my fertility or long-term health?

A simple next step

Fibroids are common—but extreme outcomes are preventable.

If you have known fibroids, regular follow-up and early discussion about symptoms or changes can help ensure timely, safe management long before complications arise.