An adnexal mass is a growth that forms in or near the ovaries, fallopian tubes, or surrounding connective tissues on either side of the uterus. These masses affect up to 20% of women at some point in their lives, and the vast majority turn out to be benign. Most are discovered incidentally during a routine pelvic exam or imaging for something else entirely, since they often cause no symptoms at all.
What Counts as an Adnexal Mass
The “adnexa” refers to the structures that sit next to the uterus: the ovaries, fallopian tubes, and the ligaments and tissues connecting them. Any abnormal lump or growth in this area falls under the umbrella of an adnexal mass. That includes fluid-filled cysts, solid tumors, and anything in between.
The most common types are ovarian cysts, particularly functional cysts that form as a normal part of the menstrual cycle when a follicle doesn’t release its egg or doesn’t shrink back down afterward. These often resolve on their own within a few cycles. Other possibilities include endometriomas (cysts filled with old blood, linked to endometriosis), benign ovarian tumors called dermoid cysts (which can contain hair, fat, or even teeth), fluid-filled sacs on or near the fallopian tubes, and fibroids that grow on a stalk and extend toward the ovary. Less commonly, an adnexal mass can represent an ectopic pregnancy or, in a small percentage of cases, ovarian cancer.
Symptoms You Might Notice
Many adnexal masses produce no symptoms and are found only when imaging is done for another reason. When symptoms do appear, abdominal or pelvic pain is by far the most common complaint, followed by nausea and vomiting. Some women experience bloating, a feeling of fullness or pressure in the pelvis, pain during sex, or changes in their menstrual cycle.
Sudden, severe pain is a different situation. It can signal ovarian torsion, where the mass causes the ovary to twist on its blood supply, cutting off circulation. This is a surgical emergency. Sharp, one-sided pelvic pain with vaginal bleeding in early pregnancy may point to an ectopic pregnancy, another condition that requires immediate care. A mass that ruptures can also cause sudden pain, sometimes with dizziness or lightheadedness from internal bleeding.
How Age Affects the Risk of Cancer
Your age and menopausal status are among the strongest predictors of whether an adnexal mass is likely to be cancerous. In premenopausal women, only about 8% of adnexal masses turn out to be malignant. That number jumps to roughly 38% in postmenopausal women. The reason is straightforward: before menopause, the ovaries are actively producing eggs and cycling through hormonal changes that regularly create and resolve cysts. After menopause, ovarian activity largely stops, so a new growth is more likely to be something that warrants closer investigation.
Diagnosis: Ultrasound and Blood Tests
Transvaginal ultrasound is the first and most important tool for evaluating an adnexal mass. It lets a clinician see the size, shape, and internal structure of the growth, all of which help determine whether it looks benign or suspicious.
Radiologists often use a standardized set of ultrasound features to classify masses. Characteristics that suggest a mass is benign include a single fluid-filled chamber with no solid parts, tiny solid components under 7 millimeters, the presence of acoustic shadows (which suggest dense tissue like a calcification), a smooth multi-chambered cyst smaller than 10 centimeters, and no detectable blood flow within the mass. On the other hand, features pointing toward malignancy include an irregular solid mass, fluid buildup in the abdomen, four or more finger-like projections (papillary structures), an irregular multi-chambered solid mass 10 centimeters or larger, and very high blood flow through the growth.
When the ultrasound picture isn’t clear, or the mass is very large (over 10 centimeters), MRI provides more detailed information without radiation.
The Role of CA-125
A blood test measuring a protein called CA-125 is often ordered alongside imaging. Levels above 35 units per milliliter are considered elevated. As a screening tool for malignancy, CA-125 has a sensitivity of about 76% and a specificity of about 80%. In practical terms, that means it correctly flags roughly three out of four cancers, but it also produces a fair number of false positives. Endometriosis, fibroids, pelvic infections, and even menstruation can all raise CA-125 levels, so an elevated result doesn’t automatically mean cancer. It’s most useful when combined with ultrasound findings and the patient’s age to build an overall risk picture.
When Monitoring Is Enough
Not every adnexal mass needs treatment. In premenopausal women, simple cysts smaller than 5 centimeters are considered normal and don’t require follow-up imaging. Even slightly larger simple cysts, up to about 7 centimeters when clearly seen on ultrasound, are typically monitored rather than treated, since they frequently resolve on their own. The rationale for watching larger cysts is partly to track their growth rate and partly because bigger cysts carry a small risk of torsion or rupture.
For postmenopausal women, the thresholds are more conservative. Simple cysts smaller than 3 centimeters generally don’t need follow-up. Those between 3 and 5 centimeters are usually monitored with repeat ultrasound. Any cyst with complex features, solid components, or blood flow in a postmenopausal woman gets more urgent attention.
Surgical Options
Surgery becomes the path forward when a mass looks suspicious for cancer, causes persistent symptoms, keeps growing, or triggers an emergency like torsion. The two main surgical approaches differ in how much tissue is removed, and the choice hinges on the findings and on whether you want to preserve fertility.
A cystectomy removes only the mass itself while leaving the ovary and fallopian tube intact. This preserves the most ovarian tissue, which matters for hormone production and for the ability to become pregnant. However, it comes with a higher chance that borderline or low-grade growths could recur, since some abnormal cells may remain in the ovary.
A salpingo-oophorectomy removes the entire ovary and fallopian tube on the affected side. This significantly reduces the risk of the mass coming back. Research shows that removing one ovary and tube does not meaningfully reduce the likelihood of pregnancy afterward, since the remaining ovary compensates. For women with borderline tumors who still want children, removing the ovary and tube on one side is often the preferred approach because it balances a lower recurrence risk with preserved fertility.
Both procedures are commonly performed laparoscopically, meaning through small incisions with a camera, which allows faster recovery than open surgery. When cancer is confirmed or strongly suspected, the operation may be more extensive and involve a gynecologic oncologist.
What to Expect After Diagnosis
If your imaging shows a simple, small cyst and your risk factors are low, you’ll likely be told to come back for a follow-up ultrasound in 6 to 12 weeks to see if it has resolved. Many do. If the mass persists but remains stable and benign-looking, periodic monitoring with ultrasound may continue for a year or more before any intervention is considered.
If the mass has features that raise concern, you’ll typically be referred to a gynecologist or gynecologic oncologist for further evaluation, which may include additional imaging, blood work, or surgery. The timeline depends on the level of suspicion: masses with clearly malignant features on ultrasound are fast-tracked, while borderline-looking masses may be reassessed in a few weeks.
The key takeaway is that finding an adnexal mass is common and, in most cases, not dangerous. The combination of ultrasound characteristics, blood markers, and your age gives clinicians a reliable way to sort masses that need attention from those that will take care of themselves.