An ovarian cyst is a fluid-filled sac that can occur within or on the surface of the ovary. Many women will develop an ovarian cyst at some time during their lives. Most cysts are benign (not cancerous), not dangerous, resolve on their own, and require no treatment. Ovarian cysts are generally painless, causing discomfort only if they twist, rupture, or bleed.
Most ovarian cysts result from hormonal changes that occur during the menstrual cycle. A follicular cyst results when a follicle that is produced in the ovary each month, does not release its egg and continues to grow until it forms a cyst. These cysts usually do not cause pain, and usually disappear without treatment after several months. A corpus luteum cyst occurs in the ovary after an egg is released. The small cyst that contained the egg seals off and tissue and fluid collect inside. This cyst usually disappears on its own, but can become large, may bleed into itself, and can cause pelvic pain. It may also rupture causing severe pain and internal bleeding.
An ovarian cyst may be detected on pelvic examination or during a pelvic ultrasound. A pelvic ultrasound uses sound waves to image the internal organs. A cyst that only contains fluid tends to be benign and unless it is very large requires no treatment. A cyst that contains more solid components usually requires further evaluation.
There are several other common types of ovarian cysts. A dermoid cyst may contain different tissues, such as hair, fat, and even teeth. They are almost always benign, but they can become very large, and can actually twist or torse causing pain. These cysts usually require surgical removal. Another common cyst is an endometrioma that usually occurs in women who have the condition “endometriosis,” where uterine lining cells grow outside the uterus. Endometriomas may become large and painful, requiring surgical treatment. Cystadenomas come from the ovarian tissue itself, and may be filled with fluid or mucus-like material. They may also become very large.
The majority of ovarian cysts are benign. There are several factors that can help predict whether or not a cyst is cancerous. The first is the size of the cyst. Very large cysts, usually greater than 9 or 10 cm, are less likely than small cysts to resolve spontaneously. If a cyst has a large number of solid components, or separations or septations, this may also be a sign of malignancy. A postmenopausal woman who develops an ovarian cyst is less likely to have a benign cyst than is a reproductive-age woman.
The treatment of an ovarian cyst depends upon the type and size of the cyst, and the woman’s age. Small cysts that are purely fluid-filled and less than 4 or 5 cm may be observed for 1-3 months and will usually resolve without treatment. Women who have a tendency to develop functional cysts are sometimes placed on oral contraceptives, which can prevent new cyst formation. In older women a cyst usually requires surgical evaluation. Surgery may also be required if a cyst is large, has solid components, is growing, or is causing pain. When ovarian cysts do require further assessment, they can usually be evaluated and treated with laparoscopic surgery, in which a narrow, telescope-like instrument is used to visualize the pelvic organs. Additional surgical instruments are placed through small incisions to perform the surgery. This is usually done under general anesthesia. Very large cysts or cysts that are more suspicious for cancer may require more extensive surgery.
SEE ALSO: Endometriosis, Laparoscopy