Ovarian cysts are small fluid-filled sacs that develop in a woman’s ovaries. Most cysts are harmless, but some may cause problems such as rupturing, bleeding, or pain; and surgery may be required to remove the cyst(s). It is important to understand the function of the ovaries and how these cysts may form.
Women normally have two ovaries that store and release eggs. Each ovary is about the size of a walnut, and one ovary is located on each side of the uterus. One ovary produces one egg each month, and this process starts a woman’s monthly menstrual cycle. The egg is enclosed in a sac called a follicle. An egg grows inside the ovary until estrogen (a hormone), signals the uterus to prepare itself for the egg. In turn, the lining of the uterus begins to thicken and prepare for implantation of a fertilized egg resulting in pregnancy. This cycle occurs each month and usually ends when the egg is not fertilized. All contents of the uterus are then expelled if the egg is not fertilized. This is called a menstrual period.
In an ultrasound image, ovarian cysts resemble bubbles. The cyst contains only fluid and is surrounded by a very thin wall. This kind of cyst is also called a functional cyst, or simple cyst. If a follicle fails to rupture and release the egg, the fluid remains and can form a cyst in the ovary. This usually affects one of the ovaries. Small cysts (smaller than one-half inch) may be present in a normal ovary while follicles are being formed.
Ovarian cysts affect women of all ages. The vast majority of ovarian cysts are considered functional (or physiologic). This means they occur normally and are not part of a disease process. Most ovarian cysts are benign, meaning they are not cancerous, and many disappear on their own in a matter of weeks without treatment. While cysts may be found in ovarian cancer, ovarian cysts typically represent a harmless (benign) condition or a normal process. Ovarian cysts occur most often during a woman’s childbearing years.
The most common types of ovarian cysts are the following:
- Follicular cyst: This type of simple cyst can form when ovulation does not occur or when a mature follicle involutes (collapses on itself). A follicular cyst usually forms at the time of ovulation and can grow to about 2.3 inches in diameter. The rupture of this type of cyst can create sharp severe pain on the side of the ovary on which the cyst appears. This sharp pain (sometimes called mittelschmerz) occurs in the middle of the menstrual cycle, during ovulation. About one-fourth of women with this type of cyst experience pain. Usually, these cysts produce no symptoms and disappear by themselves within a few months.
- Corpus luteum cyst: This type of functional ovarian cyst occurs after an egg has been released from a follicle. After this happens, the follicle becomes what is known as a corpus luteum. If a pregnancy doesn’t occur, the corpus luteum usually breaks down and disappears. It may, however, fill with fluid or blood and persist on the ovary. Usually, this cyst is found on only one side and produces no symptoms.
- Hemorrhagic cyst: This type of functional cyst occurs when bleeding occurs within a cyst. Symptoms such as abdominal pain on one side of the body may be present with this type of cyst.
- Dermoid cyst: This is a type of benign tumor sometimes referred to as mature cystic teratoma. A dermoid cyst can contain other types of growths of body tissues such as fat and occasionally bone, hair, and cartilage. The ultrasound image of this cyst type can vary because of the spectrum of contents, but a CT scan and magnetic resonance imaging (MRI) can show the presence of fat and dense calcifications. These cysts can become inflamed. They can also twist around (a condition known as ovarian torsion), compromising their blood supply and causing severe abdominal pain.
Endometriomas or endometrioid cysts: Part of the condition known as endometriosis, this type of cyst is formed when endometrial tissue (the lining tissue of the uterus) is present on the ovaries. It affects women during the reproductive years and may cause chronic pelvic pain associated with menstruation.
Endometriosis is the presence of endometrial glands and tissue outside the uterus. Women with endometriosis may have problems with fertility. Endometrioid cysts, often filled with dark, reddish-brown blood, may range in size from 0.75-8 inches.
Polycystic-appearing ovary: Polycystic-appearing ovary is diagnosed based on its enlarged size – usually twice that of normal – with small cysts present around the outside of the ovary. This condition can be found in healthy women and in women with hormonal (endocrine) disorders. An ultrasound is used to view the ovary in diagnosing this condition.
Polycystic-appearing ovary is different from the polycystic ovarian syndrome (PCOS), which includes other symptoms and physiological abnormalities in addition to the presence of ovarian cysts. Polycystic ovarian syndrome involves metabolic and cardiovascular risks linked to insulin resistance. These risks include increased glucose tolerance, type 2 diabetes, and high blood pressure.
Polycystic ovarian syndrome is associated with infertility, abnormal bleeding, increased incidences of miscarriage, and pregnancy-related complications.
Polycystic ovarian syndrome is extremely common and is thought to occur in 4%-7% of women of reproductive age
The tests other than an ultrasound alone are required to diagnose polycystic ovarian syndrome.
Cystadenoma: A cystadenoma is a type of benign tumor that develops from ovarian tissue. They may be filled with a mucous-type fluid material. Cystadenomas can become very large and require surgical removal.
Ovarian Cysts Causes
The following are possible risk factors for developing ovarian cysts:
- History of previous ovarian cysts
- Irregular menstrual cycles
- Increased upper body fat distribution
- Hypothyroidism or hormonal imbalance
- Tamoxifen therapy for breast cancer
Oral contraceptive/birth control pill use decreases the risk of developing ovarian cysts because they prevent the ovaries from producing eggs during ovulation.
Ovarian Cysts Symptoms
Usually ovarian cysts do not produce symptoms and are found during a routine physical exam or are seen by chance on an ultrasound performed for other reasons. However, the following symptoms may be present:
- Lower abdominal or pelvic pain, which may start and stop and may be severe, sudden, and sharp
- Irregular menstrual periods
- Feeling of lower abdominal or pelvic pressure or fullness
- Long-term pelvic pain during menstrual period that may also be felt in the lower back
- Pelvic pain after strenuous exercise or sexual intercourse
- Pain or pressure with urination or bowel movements
- Nausea and vomiting
- Vaginal pain or spotty bleeding from the vagina
Ovarian Cysts Diagnosis
A health care practitioner may perform the following tests to determine if a woman has an ovarian cyst or to help characterize the type of cyst that is present:
Clinical assesment by pervaginal examination and perabdominal examination are mandatory for any pelvic pathology.
- Transvaginal ultrasound: This type of imaging test is a special form of ultrasound developed to examine the pelvic organs and is the best test for diagnosing an ovarian cyst. A cyst can be diagnosed based on its appearance on the ultrasound. An Transvaginal ultrasound is a painless procedure that resembles a pelvic exam. A thin, covered wand or probe is placed into the vagina, and the examiner directs the probe toward the uterus and ovaries. This type of ultrasound produces a better image than a scan through the abdominal wall can because the probe can be positioned closer to the ovaries. Using an transvaginal ultrasound, the internal cystic structure may be categorized as simple (just fluid filled), complex (with areas of fluid mixed with solid material), or completely solid (with no obvious fluid).
- Other imaging: CT scanning aids in assessing the extent of the condition. MRI scanning may also be used to clarify results of an ultrasound.
- Serum CA-125 assay: This blood test checks for a substance called CA-125, which is associated with ovarian cancer (the CA stands for cancer antigen). This test is used in the assessment of epithelial ovarian cancer and may help determine if an ovarian mass is harmless or cancerous. However, sometimes benign conditions such as endometriosis or uterine fibroids may result in the elevated levels of CA-125 in the blood, so the test does not positively establish the diagnosis of ovarian cancer. There are some specific markers for ovarian cysts which arise from germ cells.
Hormone levels: A blood test to check LH, FSH, estradiol, and testosterone levels may indicate potential problems concerning these hormone levels.
Ovarian Cysts Treatment
Functional ovarian cysts are the most common type of ovarian cyst. They usually disappear by themselves and seldom require treatment. Growths that become abnormally large or last longer than a few months should be removed or examined to determine if they are a sign of a more serious condition.
Ovarian Cyst Medical Management
Oral contraceptives: Birth control pills may be helpful to regulate the menstrual cycle, prevent the formation of follicles that can turn into cysts, and possibly reduce the size of an existing cyst.
Pain relievers: Anti-inflammatory medication may help reduce pelvic pain.
Surgical management of ovarian cysts:
- Laparoscopic surgery: The surgeon makes small incisions through which a thin scope (laparoscope) can pass into the abdomen. The surgeon identifies the cyst through the scope and may remove the cyst or take a sample from it.
- Polycystic ovaries not responding to medical management can be drilled laparoscopically.
- Endometriotic cysts require laparoscopic cyst excision or cyst wall ablation and fulguration of endometriotic implants.
- Cystadenomas require cyst excision or in suspicious cases of malignancy may require removal of the ovary
- Dermoid cyst require excision irrespective of the size. The dermoid cyst can be excised and removed in an endobag to prevent spillage of the contents into the abdomen.
- Laparotomy: This is a more invasive surgery in which an incision is made through the abdominal wall in order to remove a cyst.
- Surgery for ovarian torsion: An ovarian cyst may twist and cause severe abdominal pain as well as nausea and vomiting. This is an emergency, surgery is necessary to correct it.
Follow-up depends largely on the type of cyst that is present. Functional cysts require follow up only or some medical treatment like oral contraceptive pills for a few cycles. Non-functional cysts need surgical management and follow up in future with ultrasonography. Cysts in premenopausal women that show no evidence of may be observed for a period of time, while suspicious-appearing cysts may warrant immediate evaluation.