“Ovarian fibroids” is a common mix-up. Fibroids are growths of the uterus, not the ovaries. But the ovaries do develop their own version of a benign solid tumor called an ovarian fibroma. If your doctor mentioned a fibroid-like mass on your ovary, this is almost certainly what they mean. Ovarian fibromas account for about 4% of all ovarian tumors, are nearly always noncancerous, and most often appear around age 48, though they can develop earlier.
Ovarian Fibromas vs. Uterine Fibroids
Uterine fibroids grow from the muscle cells of the uterine wall and are extremely common, affecting up to 70% of women by age 50. Ovarian fibromas are a completely different growth. They develop from connective tissue cells within the ovary’s supporting structure, specifically from fibroblasts in the ovarian stroma. Despite the similar-sounding names, these are distinct conditions with different origins, different behaviors, and different management approaches.
One key clinical difference: uterine fibroids can be multiple (some women have dozens), while ovarian fibromas are typically solitary. They also look different on imaging. On MRI, ovarian fibromas absorb contrast dye much less than uterine fibroids do, which helps radiologists tell them apart when the picture isn’t clear. A contrast uptake below 75% strongly suggests a fibroma rather than a fibroid, with about 92% accuracy.
What Ovarian Fibromas Feel Like
Many ovarian fibromas cause no symptoms at all and are discovered incidentally during imaging for something else. When they do cause problems, pelvic pain or a sense of pressure is the most common complaint. Larger fibromas, particularly those over 6 cm, are more likely to produce noticeable symptoms simply because they take up more space in the pelvis.
The more serious symptom risk is ovarian torsion, where the weight of the fibroma causes the ovary to twist on its own blood supply. Torsion produces sudden, sharp pelvic pain and is a medical emergency requiring prompt treatment to save the ovary. This is relatively uncommon but worth knowing about, particularly if you’ve been told you have a larger fibroma.
Meigs Syndrome: A Rare Complication
About 10 to 15% of ovarian fibromas trigger a condition called Meigs syndrome, where fluid accumulates in two places it shouldn’t: the abdominal cavity and the space around the lungs. This combination of an ovarian fibroma plus abdominal fluid plus fluid around the lungs can look alarmingly like advanced ovarian cancer on initial evaluation, which sometimes leads to misdiagnosis.
The important distinction is that Meigs syndrome resolves completely once the fibroma is removed. The fluid buildup is a reaction to the tumor, not a sign of cancer spreading. If you’ve been told you have an ovarian mass with fluid collections and your medical team is concerned about malignancy, knowing that Meigs syndrome exists can help frame the conversation with your doctor about what the findings might actually represent.
How Ovarian Fibromas Are Diagnosed
Ultrasound is usually the first imaging tool, but ovarian fibromas can be tricky to identify this way because their ultrasound appearance is often nonspecific. A solid mass on the ovary seen on ultrasound could be several things, so MRI is frequently the next step to narrow down the diagnosis.
On MRI, ovarian fibromas have a characteristic look. They appear well-defined, averaging about 6 by 5 cm in size. Most appear dark on both types of standard MRI sequences, which reflects their dense, fibrous makeup. About 63% have a visible capsule, or outer shell, and roughly two-thirds show signs of internal degenerative changes, particularly in larger tumors. Larger fibromas (over 6 cm) are also more likely to have small cystic areas near their surface, which on closer pathological examination turn out to be swollen tissue or trapped follicles rather than anything concerning.
The challenge is that any solid ovarian mass raises the question of cancer. Ovarian fibromas can mimic malignant tumors on imaging, especially when accompanied by fluid collections. The low contrast enhancement on MRI is one of the most reliable clues that the mass is a fibroma and not something more serious.
Treatment and Surgical Options
Small, symptom-free ovarian fibromas can often be monitored with periodic imaging rather than treated immediately. Surgery becomes the recommendation when fibromas cause pain, grow large enough to risk torsion, or when the diagnosis is uncertain and cancer needs to be ruled out.
For women past childbearing age, removing the entire affected ovary is the standard approach. For younger women who want to preserve fertility, a more conservative surgery that removes just the fibroma while leaving the rest of the ovary intact is an effective option. This ovary-sparing approach has a recurrence rate of only about 2%, based on long-term follow-up data. In the rare case of recurrence, it tends to appear years later (one study documented it at 50 months after the initial surgery), so ongoing monitoring with periodic ultrasound is reasonable after conservative surgery.
Long-Term Outlook
The prognosis for ovarian fibromas is excellent. These are benign tumors, and surgical removal is essentially curative. Even a subtype called “mitotically active cellular fibroma,” which has some microscopic features that look more aggressive under the microscope, carries very low risk and is distinct from the truly malignant version (fibrosarcoma). Ovarian fibromas are uncommon before age 30 and rare enough overall that many gynecologists see only a handful in their careers, which is partly why they can be initially mistaken for something more worrisome. If you’ve been told you have one, the overwhelming likelihood is a straightforward, benign condition with a simple surgical fix if it ever needs treatment at all.