About Ovarian Cysts

WHAT ARE OVARIAN CYSTS?
An ovarian cyst is simply a collection of fluid within the normally solid ovary. There are many different types of ovarian cysts, and they are an extremely common gynecologic problem. Because of the fear of ovarian cancer, cysts are a common cause of concern among women. But, it is important to know that the vast majority of ovarian cysts are not cancer and almost all ovarian cysts will go away by themselves without any treatment. However, some benign cysts will require treatment and in quite rare cases others may be cancerous.

WHAT CAUSES MOST OVARIAN CYSTS?
The most common types of ovarian cysts are called functional cysts, which result from a collection of fluid forming around a developing egg. For unknown reasons, sometimes the cells that surround an egg in the ovary form too much fluid that expands the ovary from within. If fluid continues to be formed, the ovary is stretched as if a balloon was being filled up with water. The normally white covering of the ovary becomes thin and smooth and appears bluish-gray. These cysts, called follicular cysts, may rarely become as large as 3 or 4 inches. The majority of these cysts, even the large ones, go away by themselves after a month or two.

Every month, after ovulation, the cells in the ovary form a structure called the corpus luteum. These cells can also produce too much fluid and form a cyst. The good news is that, like follicular cysts, practically all corpus luteum cysts will go away by themselves in a few weeks.

CAN A CYST CAUSE PAIN?
Although many cysts cause no symptoms at all, pressure or pain in the pelvic area is a common symptom. As fluid collects in a cyst and makes the ovary expand, the covering of the ovary is stretched, causing discomfort or pain. In very rare cases, the covering of the ovary tears opens, or ruptures, releasing the cyst fluid into the abdominal cavity, causing sudden pain.

WHAT ARE SOME OTHER TYPES OF OVARIAN CYSTS?
There are other types of benign cysts that will not go away by themselves and may need to be removed to prevent further problems. Sometimes, the cells that make up the outside coating of the ovary get trapped inside the ovary after ovulation. The trapped cells may form fluid which collects within the ovary forming a cyst. The cyst cells must be surgically removed in order to stop the production of the fluid and prevent further growth of the cyst.

WHAT IS A HEMORRHAGIC CYST?
Sometimes during the growth of a follicular or corpus luteum cyst, the tissue within the ovary tears as it is stretched and begins to bleed. The blood becomes trapped within the cyst forming what is called a hemorrhagic cyst. The bleeding may occur quickly and rapidly stretch the covering of the ovary causing pain. As the blood collects within the ovary clots are formed which can be seen on a sonogram. This type of cyst will almost always go away by itself, but it may take a few weeks or even months to do so. In rare cases, the cyst causes enough discomfort so that surgery to remove the cyst may be needed.

WHAT IS A DERMOID CYST?
The idea of a dermoid cyst is somewhat startling. For reasons we don't understand, the cells of the ovary can, all by themselves and without the presence of any sperm, start to produce hair, teeth, fluid, and other growing tissues to form an ovarian cyst. This is called a dermoid cyst. Dermoid cysts are fairly common, occurring most often before menopause and are almost never cancerous (less than 1/1000). Dermoid cysts have a fairly characteristic appearance on sonogram and often the diagnosis can be made this way. Unfortunately, these cysts do not go away by themselves and surgery is recommended when they are found.

CAN ENDOMETRIOSIS CAUSE AN OVARIAN CYST?
In some women uterine lining cells can go out the wrong way through the fallopian tubes and end up in the abdominal cavity. If these cells survive, they may attach to the outside of the uterus, tubes or ovaries, and begin to grow. During subsequent menstrual cycles, the cells are stimulated to grow and bleed just as the lining cells within the uterus continue to do. This is called endometriosis.

If these cells get trapped within the ovary, the blood has nowhere to go, so it collects within the ovary, forming a cyst called an endometrioma. As the blood ages within the cyst, it becomes dark brown and thick and the cyst is sometimes referred to as a chocolate cyst. The pattern of this blood looks distinctive on a sonogram and the diagnosis can often be suggested by that test. Sometimes endometriosis within the ovary may be painless and only discovered at the time of a routine examination. While this condition is not dangerous, endometriosis can lead to pelvic pain and/or infertility and should be appropriately treated. The treatment for endometriosis of the ovary involves removal of the cyst, often by laparoscopic surgery.

OVARIAN CYSTS AND CANCER
Research shows that benign cysts do not turn into cancerous cysts, so if you have an ovarian cyst that seems to be benign upon exam and on a sonogram, waiting for it to go away for two months or so is not risky. Research also shows that women who form benign ovarian cysts are not any more likely to develop ovarian cancer than women who have not ever had cysts.

While frightening, ovarian cancer is a rare disease. Only one out of every 15,000 women at the age of thirty will be found to have the disease. At 40, only one of every 10,000 women has this disease, and at age 60, only one of every 1500 women will be found to have it. Therefore, if a premenopausal woman is found to have a cyst in her ovary, it is overwhelmingly likely that it is benign. Even for a postmenopausal woman, an ovarian cyst has more than a 70% chance of being benign. However, cancer can develop in the ovary and its diagnosis and treatment are discussed fully in our book A Gynecologist's Second Opinion LINK.

CAN AN OVARIAN CYST FORM AFTER MENOPAUSE?
Benign ovarian cysts can still occur after menopause. In fact, after menopause the most likely types of ovarian cysts are still benign cysts and many of these will go away by themselves. However, because the incidence of ovarian cancer increases with age, any cyst or growth in the ovary after the menopause should be fully evaluated. A sonogram can be helpful in predicting whether the cyst is benign, or if it is suspicious for cancer. After menopause, the blood test CA-125 should be done because it is more accurate in postmenopausal women. If the cyst shows a benign pattern on sonogram and the CA-125 test is normal, then the ovarian cyst is usually