Ovarian cysts are common, yet often misunderstood. A big part of the confusion around ovarian cysts is that cyst formation is abnormal. In reality, cyst formation is a regular part of the menstrual cycle. An ovulating woman makes a new cyst every month!
A cyst is simply a fluid-filled sac with a lining – something like a water balloon placed within the ovary. The majority of ovarian cysts are a normal part of the monthly maturation of an egg. The technical name for this cyst is a follicle.
Follicles always develop around an egg. As the cells that surround and support the egg multiply, they begin to secrete fluid. This fluid pushes the cells to the outside thus forming the lining of the cyst and enclosing the egg within the follicle wall. When the egg is ready to ovulate, it is contained within the wall of a fluid-filled sac. This fluid-filled sac will measure about 2cm in diameter and occupy about one-third to one-half of the ovarian volume. If the follicle containing the ovum doesn’t rupture during ovulation, a follicle cyst of more than 2.5cm diameter may result.
After ovulation, the egg releases into the pelvis and the follicle may once again fill up with fluid or blood and persist. This generally lasts for another week or two, but it can be much longer than that. Sometimes the follicle can fail to rupture and the fluid-filled sac can remain for a few weeks. For some women, the rupture of an ovarian cyst can be painful enough to require a visit to the emergency room. Rarely, some may even require surgery to stop bleeding from the cyst.
Most cysts are part of a normal ovulatory cycle. However, some cysts form as damage to the surface of the ovary. This is how other cell types get under the ovary surface and accumulate fluid (sometimes blood) within the cyst.
Most ovarian cysts are temporary structures and, if left on their own, will fade away within a week or two. Some cysts, however, can persist for several months. Many of these cysts will have a wall that continues to be active in secreting fluid and may cause the cyst to remain or even grow in size. On rare occasions, a cluster of cyst wall cells will divide more rapidly than normal (a process called neoplasia, or new cell growth) and, over time, can develop pre-cancerous changes or even become ovarian cancer – although even most neoplastic cyst walls are benign.
The small, but not negligible, risk that a cyst could contain some cancerous cells is what makes them potentially worrisome. For most women of reproductive age, ovarian cysts are more of an inconvenience than something to worry about. However, cysts that become very large, or have been present for several months, are at greater risk to contain neoplastic changes and thus have higher cancer risks.
An ultrasound can be useful and continues to get better at detecting neoplasia. Ultrasounds are not very good, however, at distinguishing between benign neoplasia and malignant neoplasia. In this case, a surgeon could remove the cyst wall for further examination by a pathologist.
While most cyst wall thickenings are benign, studies show that for every ovarian cancer detected early, about 8-10 patients will undergo a surgery they probably didn’t need. However, early detection of cancer can be life-saving for patients. There are some blood tests like CA-125 that can be of some value in determining the likelihood of cancer is present, but these are still not nearly as specific as we would like. There is still great debate as to how valuable ultrasound and CA-125 are as cancer screening tools.
For women under 45, cysts that haven’t been present within 6 months can be drained with an in-office procedure. This procedure can take about 5 minutes and provides significant pain relief. However, because only the fluid was removed (and not the cyst wall), there is still a 15-20% chance the fluid may re-collect. Keep in mind, that in reproductive-age women, there will always be a few very small cysts. Those are simply immature follicles waiting to grow towards ovulation.
For women over 45, treatment options may differ. Cysts less than 2cm in size rarely cause issues and generally need no treatment. Sometimes a follow-up ultrasound is recommended to ensure the cyst has resolved on its own. For cysts that are more than 4cm in size, traditional surgery may be needed for removal. This is often the case if there was no prior ultrasound to prove the cyst had not been present for less than 6 months, or if there is thickening noted in the cyst wall.
A: Risks of developing ovarian cysts can be heightened by the following:
A: Although most cysts do not cause symptoms, there are a few things to look out for:
We suggest that you seek immediate medical attention if you experience sudden abdominal or pelvic pain, fever, or vomiting.
A: There are many different types of ovarian cysts (dermoid, hemorrhagic, endometriomas, cystadenomas), but the most common are called functional cysts. The two different types of functional cysts are:
A: If your doctor suspects that you may have a cyst, they will begin by completing a pelvic exam to look for swelling. Since cysts do not often require treatment, there are a number of different options the doctor can choose between:
A: The majority of ovarian cysts will go away on their own and do not require treatment. However, if the ovarian cyst does not go away or continues to grow, there are a few options for treatment.