Yes, certain types of ovarian cysts can persist for years, sometimes even decades, without causing symptoms. The key factor is what kind of cyst you’re dealing with. Functional cysts, the most common type, typically resolve on their own within two to three menstrual cycles. But several other types are built differently and won’t disappear without treatment.
Functional Cysts Resolve Quickly
The ovarian cysts most people develop are functional cysts, which form as a normal part of ovulation. These thin-walled, fluid-filled sacs usually measure less than 5 centimeters and disappear within two to three menstrual cycles without any intervention. If a simple cyst hasn’t resolved after a few months, it’s less likely to be a functional cyst and more likely something else entirely. A Cochrane review of multiple trials found that persistent cysts tend to be pathological (such as endometriomas or other structural cysts) rather than physiological.
Types That Can Last for Years
Dermoid Cysts
Dermoid cysts (also called mature cystic teratomas) are among the most common cysts that stick around. They contain tissue like hair, skin cells, and even teeth, because they develop from the same type of cells that form human tissue during embryonic development. In premenopausal women, dermoid cysts grow at an average rate of about 1.8 millimeters per year. That’s slow enough that a small dermoid cyst could sit quietly on an ovary for many years before it’s large enough to notice. In postmenopausal women, dermoid cysts don’t grow at a statistically significant rate at all, meaning they can remain essentially unchanged indefinitely.
Dermoid cysts smaller than 6 centimeters in premenopausal women can generally be monitored safely over time rather than removed immediately.
Endometriomas
Endometriomas, sometimes called chocolate cysts because of the dark, old blood they contain, are linked to endometriosis. These cysts form when tissue similar to the uterine lining grows on or inside the ovary. They do not resolve the way functional cysts do. Left untreated, endometriomas can gradually grow larger over time and lead to worsening pain. Smaller, stable endometriomas may be monitored with repeat imaging, but they rarely disappear on their own. Some people live with them for years, particularly if symptoms are mild or manageable.
Cystadenomas
Cystadenomas are benign tumors that grow from the surface of the ovary. The mucinous type, which is filled with thick, sticky fluid, accounts for roughly 10 to 15 percent of benign ovarian growths. These cysts don’t resolve spontaneously and can grow quite large. The average size at the time they’re discovered is 18 centimeters, and in rare cases they can fill the entire abdominal cavity. Mucinous cystadenomas most commonly appear in women in their twenties through forties but have been found in adolescents and postmenopausal patients alike. Because they’re benign but won’t go away, they can technically be present for years before they grow large enough to cause symptoms.
Birth Control Pills Won’t Shrink Existing Cysts
A common misconception is that hormonal birth control can treat a persistent cyst. While older oral contraceptives were associated with fewer new functional cysts forming, multiple clinical trials have shown that birth control pills do not help existing cysts resolve any faster. This held true for both cysts that developed spontaneously and those triggered by fertility treatments. If your cyst hasn’t gone away on its own after a few cycles, the pill won’t change that.
How Persistent Cysts Are Monitored
For simple cysts that appear on an ultrasound, monitoring recommendations depend on size and whether you’re pre- or postmenopausal. In reproductive-age women, cysts up to 5 centimeters are considered almost certainly benign and don’t require follow-up imaging. Cysts between 5 and 7 centimeters are still very unlikely to be harmful but are typically tracked with a yearly ultrasound. Anything over 7 centimeters may need additional imaging with MRI or a surgical evaluation, since larger cysts are harder to assess fully on ultrasound alone.
For postmenopausal women, the thresholds are more conservative. Cysts under 1 centimeter are considered clinically insignificant. Cysts between 1 and 7 centimeters are monitored with yearly ultrasound, at least initially, with the option to reduce the frequency once the cyst has been stable for a period of time. Over 7 centimeters, the same recommendation for further imaging or surgical evaluation applies.
Cancer Risk With Long-Lasting Cysts
If you’ve had a cyst for years without changes, the cancer risk is extremely low. A study of women aged 50 and older with stable masses found an ovarian cancer rate of just 0.27 percent. The longer a mass stayed the same size on ultrasound, the lower the risk became. After 52 weeks of documented stability, no cancer cases were observed at all. This is why many experts consider the benefit of continued yearly imaging beyond 12 months of stability to be minimal for cysts that haven’t changed.
When Surgery Becomes the Recommendation
Size is the primary trigger for surgical removal. Cysts larger than 5 to 6 centimeters carry an increased risk of ovarian torsion, where the weight of the cyst causes the ovary to twist on itself, cutting off its blood supply. Up to 85 percent of people diagnosed with ovarian torsion have cysts or benign masses on their ovaries.
For dermoid cysts and other benign growths, the standard approach is to remove the cyst while preserving the ovary, particularly in younger women. Cysts above 10 centimeters are more likely to require an open surgical incision rather than a minimally invasive approach. In postmenopausal women, or when a cyst is very large and the ovary can’t be saved, removal of the entire ovary is the usual recommendation.
A cyst that has been stable for years, remains small, and causes no symptoms may never need surgery. But one that’s growing steadily, causing pain, or reaching a size where torsion becomes a realistic concern will typically prompt a conversation about removal.