An ovarian cyst is a fluid-filled sac within the ovary. They usually cause no symptoms, but occasionally they may produce bloating, lower abdominal pain, or lower back pain. The majority of cysts are harmless. If the cyst either breaks open or causes twisting of the ovary, it may cause severe pain. This may result in vomiting or feeling faint.
Most ovarian cysts are related to ovulation, being either follicular cysts or corpus luteum cysts. Other types include cysts due to endometriosis, dermoid cysts, and cystadenomas. Many small cysts occur in both ovaries in polycystic ovary syndrome (PCOS). Pelvic inflammatory disease may also result in cysts. Rarely, cysts may be a form of ovarian cancer. Diagnosis is undertaken by pelvic examination with a pelvic ultrasound or other testing used to gather further details.
Often, cysts are simply observed over time. If they cause pain, medications such as paracetamol (acetaminophen) or ibuprofen may be used. Hormonal birth control may be used to prevent further cysts in those who are frequently affected. However, evidence does not support birth control as a treatment of current cysts. If they do not go away after several months, get larger, look unusual, or cause pain, they may be removed by surgery.
Most women of reproductive age develop small cysts each month. Large cysts that cause problems occur in about 8% of women before menopause. Ovarian cysts are present in about 16% of women after menopause, and, if present, are more likely to be cancerous.
Signs and symptoms
Ovarian cysts tend to produce non-specific symptoms (i.e., symptoms that could be caused by a large number of conditions). Some or all of the following symptoms may be present, though it is possible not to experience any symptoms: Abdominal pain. Dull aching pain within the abdomen or pelvis, especially during intercourse. Uterine bleeding. Pain during or shortly after beginning or end of menstrual period; irregular periods, or abnormal uterine bleeding or spotting. Fullness, heaviness, pressure, swelling, or bloating in the abdomen. Some ovarian cysts become large enough to cause the lower abdomen to visibly swell. When a cyst ruptures from the ovary, there may be sudden and sharp pain in the lower abdomen on one side. Large cysts can cause a change in frequency or ease of urination (such as inability to fully empty the bladder), or difficulty with bowel movements due to pressure on adjacent pelvic anatomy. Constitutional symptoms such as fatigue, headaches. Nausea or vomiting Weight gain Other symptoms may depend on the cause of the cysts: Symptoms that may occur if the cause of the cysts is polycystic ovarian syndrome (PCOS) may include increased facial hair or body hair, acne, obesity and infertility. If the cause is endometriosis, then periods may be heavy, and intercourse painful.
The effect of cysts not related to PCOS on fertility is unclear.
In other cases, the cyst is asymptomatic, and is discovered incidentally while doing medical imaging for another condition. Ovarian cysts and other "incidentalomas" of the uterine adnexa appear in almost 5% of CT scans done on women.
Complications The most common complications are cyst rupture, which occasionally leads to internal bleeding ("hemorrhagic cyst"), and ovarian torsion.
Cyst rupture When the surface of cyst breaks, the contents can leak out; this is called a ruptured cyst. The main symptom is abdominal pain, which may last a few days to several weeks, but they can also be asymptomatic.
A ruptured ovarian cyst is usually self-limiting, and only requires keeping an eye on the situation and pain medications for a few days, while the body heals itself. Rupture of large ovarian cysts can cause bleeding inside the abdominal cavity. Rarely, enough blood will be lost that the bleeding will produce hypovolemic shock, which can be a medical emergency requiring surgery. However, normally, the internal bleeding is minimal and requires no intervention.
Ovarian torsion Ovarian torsion is a very painful medical condition requiring urgent surgery. It can be caused by a pedunculated ovarian cyst that twisted in a way that cuts off the blood flow. It is most likely to be seen in women of reproductive age, though it has happened in young girls (premenarche) and postmenopausal women. Ovarian torsion may be more likely during pregnancy, especially during the third and fourth months of pregnancy, as the internal anatomy shifts to accommodate fetal growth. Diagnosis relies on clinical examination and ultrasound imaging.
Cysts larger than 4 cm are associated with approximately 17% risk.
Types
There are many types of ovarian cysts, some of which are normal and most of which are benign (non-cancerous).
Functional Functional cysts form as a normal part of the menstrual cycle. There are several types of functional cysts: Follicular cyst, the most common type of ovarian cyst. In menstruating women, an ovarian follicle containing the ovum (an unfertilized egg) normally releases the ovum during ovulation. If it does not release the ovum, a follicular cyst of more than 2.5 cm diameter may result. A ruptured follicular cyst can be painful. A luteal cyst is a cyst that forms after ovulation, from the corpus luteum (the remnant of the ovarian follicle, after the ovum has been released). A luteal cyst is twice as likely to appear on the right side. It normally resolves during the last week of the menstrual cycle. A corpus luteum that is more than 3 cm is abnormal. Theca lutein cysts occur within the thecal layer of cells surrounding developing oocytes. Under the influence of excessive hCG, thecal cells may proliferate and become cystic. This is usually on both ovaries.
Non-functional Non-functional cysts may include the following: An ovary with many cysts, which may be found in normal women, or within the setting of polycystic ovary syndrome Cysts caused by endometriosis, known as chocolate cysts Hemorrhagic ovarian cyst Dermoid cyst – the most common non-functional ovarian cyst, especially for women under the age of 30, they are benign (non-cancerous) with varied morphology. They can usually be diagnosed from ultrasound alone. Depending on size, growth rate (usually slow), and the age of the woman, treatment might involve surgical removal or watchful waiting. They are also called mature cystic teratomas. Ovarian serous cystadenoma – more common in women between the age of 30 and 40. Ovarian mucinous cystadenoma – although there is usually only one of these, they can grow very large, with diameters sometimes exceeding 50 cm (20 inches). Paraovarian cyst Cystic adenofibroma Borderline tumoral cysts
Risk factors Risk factors include fertility status (more common in women of childbearing age) and irregular menstrual cycles. Using combined hormonal contraception may reduce the risk, especially with high-dose pills, but it does not treat existing cysts.
Diagnosis
Ovarian cysts are usually diagnosed by pelvic ultrasound, CT scan, or MRI, and correlated with clinical presentation and endocrinologic tests as appropriate. Ultrasound is the most important imaging modality, as abnormalities seen in a CT scan sometimes prove to be normal in ultrasound. If a different modality is needed, then MRIs are more reliable than CT scans.
Ultrasound Usually, an experienced sonographer can readily identify benign ovarian cysts, often with a level of accuracy that rivals other approaches.
Follow-up imaging in women of reproductive age for incidentally discovered simple cysts on ultrasound is not needed until 5 cm, as these are usually normal ovarian follicles. Simple cysts 5 to 7 cm in premenopausal females should be followed yearly. Simple cysts larger than 7 cm require further imaging with MRI or surgical assessment. Because they are large, they cannot be reliably assessed by ultrasound alone; it can be difficult to see posterior wall soft tissue nodularity or thickened septation due to limited ultrasound beam penetrance at this size and depth. For the corpus luteum, a dominant ovulating follicle that typically appears as a cyst with circumferentially thickened walls and crenulated inner margins, follow up is not needed if the cyst is less than 3 cm in diameter. In postmenopausal women, any simple cyst greater than 1 cm but less than 7 cm needs yearly follow-up, while those greater than 7 cm need MRI or surgical evaluation, similar to reproductive age females.
For incidentally discovered dermoids, diagnosed on ultrasound by their pathognomonic echogenic fat, either surgical removal or yearly follow up is indicated, regardless of the woman's age. For peritoneal inclusion cysts, which have a crumpled tissue-paper appearance and tend to follow the contour of adjacent organs, follow up is based on clinical history. Hydrosalpinx, or fallopian tube dilation, can be mistaken for an ovarian cyst due to its anechoic appearance. Follow-up for this is also based on clinical presentation.
For multilocular cysts with thin septation less than 3 mm, surgical evaluation is recommended. The presence of multiloculation suggests a neoplasm, although the thin septation implies that the neoplasm is benign. For any thickened septation, nodularity, vascular flow on color doppler, or growth over several ultrasounds, surgical removal may be considered due to concern of cancer.
Scoring systems Most ovarian cysts are not malignant; however, some do become cancerous. There are several systems to assess risk of an ovarian cyst of being an ovarian cancer, including the RMI (risk of malignancy index), LR2 and SR (simple rules). Sensitivities and specificities of these systems are given in tables below:
Scoring systems Premenopausal Postmenopausal Sensitivity Specificity Sensitivity Specificity RMI I 44% 95% 79% 90% LR2 85% 91% 94% 70% SR 93% 83% 93% 76%
Ovarian cysts may be classified according to whether they are a variant of the normal menstrual cycle, referred to as a functional or follicular cyst.
Ovarian cysts are considered large when they are over 5 cm and giant when they are over 15 cm. In children, ovarian cysts reaching above the level of the umbilicus are considered giant.
Associated conditions In juvenile hypothyroidism multicystic ovaries are present in about 75% of cases, while large ovarian cysts and elevated ovarian tumor marks are one of the symptoms of the Van Wyk and Grumbach syndrome.
The CA-125 marker in children and adolescents can be frequently elevated even in absence of malignancy and conservative management should be considered.
Polycystic ovarian syndrome involves the development of multiple small cysts in both ovaries due to an elevated ratio of leutenizing hormone to follicle stimulating hormone, typically more than 25 cysts in each ovary, or an ovarian volume of greater than 10 mL.
Larger bilateral cysts can develop as a result of fertility treatment due to elevated levels of HCG, as can be seen with the use of clomifene for follicular induction, in extreme cases resulting in a condition known as ovarian hyperstimulation syndrome. Certain malignancies can mimic the effects of clomifene on the ovaries, also due to increased HCG, in particular gestational trophoblastic disease. Ovarian hyperstimulation occurs more often with invasive moles and choriocarcinoma than complete molar pregnancies.
Risk of cancer Accurately differentiating a cyst from a cancer is critical to management. Medical imaging showing a simple, smooth bubble of watery liquid is characteristic of a benign cyst. If the cyst is large, is multilocular, or has complex internal features, such as papillary (bumpy) projections into the cyst or solid areas inside the cyst, it is more likely to be cancerous.