Ovarian Cysts
Ovarian cysts facts
- Ovarian cysts are closed, sac-like structures within the ovary that are filled with a liquid or semisolid substance.
- Ovarian cysts form for numerous reasons.
- Pain in the abdomen or pelvis is the most common symptom of an ovarian cyst, but most are asymptomatic.
- Most cysts are diagnosed byultrasound or physical exam.
- The treatment of an ovarian cyst depends upon its likely diagnosis and varies from observation and monitoring to surgical treatment.
What is the ovary and what are ovarian cysts?
The ovary is one of a pair of reproductive glands in women that are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of a walnut. The ovaries produce eggs (ova) and female hormones estrogen and progesterone. The ovaries are the main source of female hormones, which control the development of female body characteristics such as the breasts, body shape, and body hair. They also regulate the menstrual cycle and pregnancy. Ovarian cysts are closed, sac-like structures within an ovary that contain a liquid, or semisolid substance. "Cyst" is merely a general term for a fluid-filled structure, which may or may not represent a tumor or neoplasm (new growth). If it is a tumor, it may be benign or malignant. The ovary is also referred to as the female gonad.
What causes ovarian cysts?
Ovarian cysts form for numerous reasons. The most common type is a follicular cyst, which results from the growth of a follicle. A follicle is the normal fluid-filled sac that contains an egg. Follicular cysts form when the follicle grows larger than normal during the menstrual cycle and does not open to release the egg. Usually, follicular cysts resolve spontaneously over the course of days to months. Cysts can contain blood (hemorrhagic cysts) from leakage of blood into the egg sac.
Another type of ovarian cyst that is related to the menstrual cycle is a corpus luteum cyst. The corpus luteum is an area of tissue within the ovary that occurs after an egg has been released from a follicle. If a pregnancy doesn't occur, the corpus luteum usually breaks down and disappears. It may, however, fill with fluid or blood and persist as a cyst on the ovary. Usually, this cyst is found on only one side, produces no symptomsand resolves spontaneously.
Endometriosis is a condition in which cells that normally grow inside as a lining of the uterus (womb), instead grow outside of the uterus in other locations. The ovary is a common site for endometriosis. When endometriosis involves the ovary, the area of endometrial tissue may grow and bleed over time, forming a blood-filled cyst with red- or brown-colored contents called an endometrioma, sometimes referred to as a chocolate cyst. The condition known as polycystic ovarian syndrome (PCOS) is characterized by the presence of multiple small cysts within both ovaries. PCOS is associated with a number of hormonal problems and is the most common cause of infertility in women.
Both benign and malignant tumors of the ovary may also be cystic. Occasionally, the tissues of the ovary develop abnormally to form other body tissues such as hair or teeth. Cysts with these abnormal tissues are really tumors called denign cystic teratomas or dermoid cysts.
Infections of the pelvic organs can involve the ovaries and Fallopian tubes. In severe cases, pus-filled cystic spaces may be present on, in, or around the ovary or tubes. These are known as tubo-ovarian abscesses.
What symptoms are caused by ovarian cysts?
Most ovarian cysts are never noticed and resolve without women ever realizing that they are there. When a cyst causes symptoms, pain in the abdomen or pelvis is the most common one. The pain can be caused from:
- rupture of the cyst,
- rapid growth and stretching,
- bleeding into the cyst, or
- twisting of the cyst around its blood supply (known as torsion).
If the cyst has reached a large size, other symptoms may arise as a result of pressure or distortion of adjacent anatomical structures. These symptoms can include abdominal fullness or bloating, indigestion, feeling full after eating only a small amount (early satiety), urinary urgency, feeling an urge to defecate or having difficult bowel movements, or pain with sexual intercourse.
How are ovarian cysts diagnosed?
Sometimes ovarian cysts may be noticed by a doctor during a bimanual examination of the pelvis. If a cyst is suspected based upon symptoms or physical examination, imaging techniques are used. Most cysts are diagnosed by ultrasound, which is the best imaging technique for detecting them. Ultrasound uses sound waves to produce an image of structures within the body. Ultrasound imaging is painless and harmless.
Cysts can also be detected with other imaging methods, such as CT scan or MRI scan (magnetic resonance imaging).
How can the physician decide if an ovarian cyst is dangerous?
If a woman is in her 40's, or younger, and has regular menstrual periods, most ovarian masses are "functional ovarian cysts," which are not really abnormal. Examples include follicular cysts and corpus luteum cysts. These are related to the process of ovulation that happens with the menstrual cycle. They usually disappear on their own during a future menstrual cycle. Therefore, especially in women in their 20's and 30's, these cysts are watched for a few menstrual cycles to verify that they disappear.
Because oral contraceptives work by preventing ovulation, physicians will not generally expect women who are taking oral contraceptives to have common "functional ovarian cysts." These women do not have functional ovarian cysts. They may receive further evaluation with pelvic ultrasound or possibly surgical intervention. Functional ovarian cysts do not occur in women after they have reached menopause. Small cystic arrested follicles may persist in the ovary after menopause.
Other factors are helpful in evaluating ovarian cysts (besides the woman's age, or whether she is taking oral contraceptives). A cyst that contains a simple sac of fluid on ultrasound is more likely to be a benign neoplasm than a cyst with solid tissue in it. So the ultrasound appearance also plays a role in determining the level of suspicion regarding an ovarian tumor.
Ovarian cancer is rare in women younger than age 40. After age 40, an ovarian cyst has a higher chance of being cancerous than before age 40, although most ovarian cysts are benign even after age 40. CA-125 blood testing can be used as a marker of ovarian cancer, but it does not always represent cancer, even when it is abnormal, and it may be normal in the presence of malignancy. CA-125 is a protein that is elevated in the bloodstream of may women with advanced ovarian cancer.
- First, many benign conditions in women of childbearing age can cause the CA-125 level to be elevated, so CA-125 is not a specific test, especially in younger women. Pelvic infections, uterine fibroids, pregnancy,, benign (hemorrhagic) ovarian cysts, endometriosis, and liver disease are some of the conditions that may elevate blood CA-125 levels in the absence of ovarian cancer.
- Second, even if the woman has an ovarian cancer, not all ovarian cancers will cause the CA-125 level to be elevated. Furthermore, CA-125 levels can be abnormally high in women with breast, lung, and pancreatic cancer.
How are ovarian cysts treated?
Most ovarian cysts in women of childbearing age are follicular or corpus luteum cysts (functional cysts) that disappear naturally in one to three months, although they can rupture and cause pain. They are benign and have no long-term medical consequence. They may be diagnosed coincidentally during a pelvic examination in women who do not have any related symptoms. All women have follicular cysts at some point that generally go unnoticed.
Ultrasound is useful to determine if the cyst is simple (just fluid with no solid tissue, suggesting a benign condition) or compound (with solid components that often requires surgical resection).
In summary, the ideal treatment of ovarian cysts depends on what the cyst is likely to be. The woman's age, the size (and any change in size) of the cyst, and the cyst's appearance on ultrasound help determine the treatment. Cysts that are functional are usually observed unless they rupture and cause significant bleeding, in which case, surgical treatment is required. Benign and malignant tumors require operation.
Treatment can consist of simple observation, or it can involve evaluating blood tests such as a CA-125 to help determine the potential for cancer (keeping in mind the many limitations of CA-125 testing described above).
The tumor can be surgically removed either with laparoscopy,, or if needed, an open abdominal incision (laparotomy) if it is causing severe pain, not resolving, or if it is suspicious in any way. Once the cyst is removed, the growth is sent to a pathologist who examines the tissue under a microscope to make the final diagnosis as to the type of cyst present.
What are the risks of ovarian cysts during pregnancy?
Ovarian cysts are sometimes discovered during pregnancy. In most cases, they are an incidental finding at the time of routine prenatal ultrasound screening. The majority of ovarian cysts found during pregnancy are benign conditions that do not require surgical intervention. However, surgery may be indicated if there is a suspicion of malignancy, if an acute complication such as rupture or torsion (twisting of the cyst, disrupting the blood supply) develops, or if the size of the cyst is likely to present problems with the pregnancy.
