Gynecologists see many consults for ovarian cysts over the course of their career. Some are for cysts or masses that are legitimate problems. Some are not. After all, the function of a normal ovary is to produce a cyst each month. Unfortunately, the ovaries can get blamed simply for doing a good job. Here's a rundown on the ovaries, when an ovarian cyst is considered normal, and when it needs further evaluation.
What is a normal ovarian cyst?
Each month, the ovaries select a number of immature eggs to develop into follicles, in preparation for ovulation. These follicles vary in size throughout the process but are usually less than a centimeter in diameter. Different circulating hormones signal one of the follicles to become dominant, further enlarge and become a mature egg ready for ovulation.
During ovulation, the mature egg is released from the ovary, leaving behind a small cyst known as a corpus luteum cyst. This is an expected finding each month in an ovulating woman. The cysts will typically occur on alternating sides of the ovary each month.
Functional cysts can enlarge to up to 10 centimeters, causing pressure-like symptoms or pain.
Normal, physiologic or "functional" cysts are simple, appear on ultrasound and range in size from 2 to 4 centimeters. These small cysts are not usually a cause of significant pain. However, functional cysts can enlarge to up to 10 centimeters, causing pressure-like symptoms or pain.
These larger functional cysts can also rupture or cause the ovary to twist on its attachments to the uterus and pelvic sidewall, cutting off blood supply to the ovary and causing severe pain. For these reasons, asymptomatic cysts larger than 5 centimeters will usually be monitored to make sure they resolve.
Other ovarian cysts
There are other causes for ovarian cysts that can result in more complex or larger cysts, which can cause symptoms including pain, pressure and irregular bleeding.
Polycystic ovaries are a result of polycystic ovary syndrome, a condition that causes irregular menstrual cycles. The ovaries do not ovulate monthly due to hormonal imbalances, and instead have multiple small follicles that can be seen on ultrasound. Polycystic ovaries tend to be mildly enlarged due to the presence of these follicles, but the follicles themselves do not require monitoring.
Hemorrhagic cysts occur when a normal ovarian cyst ruptures a blood vessel during the process of ovulation and blood collects within the cyst. These can become enlarged, painful and occasionally rupture, though many of them self-resolve. They are easily diagnosed on ultrasound due to their classic appearance.
Dermoid cysts contain different types of cell lines, resulting in different tissues being contained within these cysts—most often fat, hair and teeth. The majority of dermoids (also known as teratomas) are benign, though a small percentage can be cancerous. They can occur on one or both sides of the ovary.
Endometriomas are ovarian cysts that contain endometrial tissue. Often called "chocolate cysts" because of the appearance of the brown endometrial fluid within them, they can cause pelvic pain, particularly associated with the menstrual cycle, as well as painful sex.
Tubo-ovarian abscesses are infectious causes of ovarian masses and typically cause pain, fever and other symptoms, such as nausea. Treatment for these cysts includes antibiotics, either as an outpatient service or, in severe cases, in the hospital.
Ovarian cancer is a very rare cause of an ovarian mass, particularly in a premenopausal woman. These tumors have very complex appearances on ultrasound and are often suspected based on a combination of imaging and bloodwork.
Treatment of ovarian cysts
Management of an ovarian cyst will depend on a patient's age and the size and appearance of the cyst. Normal physiologic cysts do not require follow-up unless they are larger than 5 centimeters, in which case they may be followed to ensure they resolve.
If a patient has frequent issues with large functional cysts or ruptured ovarian cysts, birth control may be prescribed to prevent future cysts from forming by suppressing ovulation.
Other benign-appearing ovarian cysts can be followed with a series of ultrasounds over time to make sure they are stable and not enlarging or becoming more complex in appearance.
Even when ovarian cysts do become problematic for patients, they are most often benign and easily managed by a gynecologist.
Surgical intervention is recommended for any cyst that is suspicious in appearance, enlarging or is becoming abnormally complex, is larger than 10 centimeters or is causing significant pain. If surgery is recommended, most often a minimally invasive technique will be used to try to remove the cyst and leave the ovary intact. If a patient has finished having children or the cyst is concerning in appearance, plans may be made to take out the affected ovary along with the cyst.
If cancer is suspected, patients may be referred to a gynecologic cancer specialist for further evaluation prior to surgery.
Remember: Every woman who is ovulating has an ovarian cyst every month. Ovarian cysts are not necessarily abnormal. Even when ovarian cysts do become problematic for patients, they are most often benign and easily managed by a gynecologist.