Ovarian Cysts

Ovarian cyst

Ovarian cyst
Classification and external resources

An ovarian cyst is any collection of fluid, surrounded by a very thin wall, within an ovary.^[1] Any ovarian follicle that is larger than about two centimeters is termed an ovarian cyst. Such cysts range in size from as small as a pea to larger than an orange.

Most ovarian cysts are functional in nature and harmless (benign).^[1][2]

Ovarian cysts affect women of all ages. They occur most often, however, during a woman's childbearing years.

Some ovarian cysts cause problems, such as bleeding and pain. Surgery may be required to remove cysts larger than 5 centimeters in diameter.

Classification

Ovarian cysts may be classified according to whether they are a variant of the normal menstrual cycle, called a functional cyst, or not.^[3]

Functional

Functional cysts form as a normal part of the menstrual cycle. Such cysts may include:

• Follicular cyst, the most common type of ovarian cyst. In menstruation, a follicle containing the ovum (unfertilized egg) will rupture during ovulation. If this does not occur, a follicular cyst of more than 2.5 cm diameter may result.^[3]
• Corpus luteum cysts appear after ovulation. The corpus luteum is the remnant of the follicle after the ovum has moved to the fallopian tubes. This normally degrades within 5–9 days. A corpus lutem that is more than 3 cm is defined as cystic.^[3]
• Thecal 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.^[3]

Non-functional

A hemorrhagic ovarian cyst, probably originating from a corpus luteum cyst, found in a woman 3 weeks into the postpartum period. The hemorrhage is discerned by a grainy texture of an higher echogenicity than the fluid in the periphery of the cyst that resembles dark crescents.

Non-functional cysts may include:

• 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
• Ovarian serous cystadenoma
• Ovarian mucinous cystadenoma
• Paraovarian cyst
• Cystic adenofibroma
• Borderline tumoral cysts

Signs and symptoms

Some or all of the following symptoms may be present, though it is possible not to experience any symptoms:^[3]

• Abdominal pain. Dull aching pain within the abdomen or pelvis, especially on 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.
• When a cyst ruptures from the ovary, there may be sudden and sharp pain in the lower abdomen on one side.
• 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:^[3]

• Symptoms that may occur if the cause of the cysts is polycystic ovarian syndrome 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.

Diagnosis

A 2cm left ovarian cyst as seen on ultrasound

An Axial CT demonstrating a large hemorrhagic ovarian cyst. The cyst is delineated by the yellow bars with blood seen anteriorly.

A CT scan showing an 8.5 cm cyst in a 29 year old female.

Ovarian cysts are usually diagnosed by either ultrasound or CT scan. Follow-up imaging for women of reproductive age with small simple or hemorrhagic cyst is generally not required.^[4]

There are several systems for scoring of the risk of an ovarian cyst of being an ovarian cancer, including RMI (risk of malignancy index), LR2 and SR (simple rules). Sensitivities and specificities of these systems are given in tables below:^[5]

Scoring systems	Premenopausal		Postmenopausal
	Sensitivity	Specificity	Sensitivity	Specificity
RMI I	44%	95%	79%	90%
LR2	85%	91%	94%	70%
SR	93%	83%	93%	76%

Risk of malignancy index

A widely recognized method of estimating the risk of malignant ovarian cancer based on initial workup is the risk of malignancy index(RMI).^[6]

It is recommended that women with an RMI score over 200 should be referred to a center with experience in ovarian cancer surgery.^[7]

The RMI is calculated as follows:^[7]

RMI = ultrasound score x menopausal score x CA-125 level in U/ml.

There are two methods to determine the ultrasound score and menopausal score, with the resultant RMI being called RMI 1 and RMI 2, respectively, depending on what method is used:^[7]

Feature	RMI 1	RMI 2
Ultrasound abnormalities: multilocular cyst solid areas bilateral lesions ascites intra-abdominal metastases	0 = no abnormality 1 = one abnormality 3 = two or more abnormalities	0 = none 1 = one abnormality 4 = two or more abnormalities
Menopausal score	1 = premenopausal 3 = postmenopausal	1 = premenopausal 4 = postmenopausal
CA-125	Quantity in U/ml	Quantity in U/ml

An RMI 2 of over 200 has been estimated to have a sensitivity of 74 to 80%, a specificity of 89 to 92% and a positive predictive value of around 80% of ovarian cancer.^[7] RMI 2 is regarded as more sensitive than RMI 1.^[7]

Treatment

About 95% of ovarian cysts are benign, meaning they are not cancerous.^[8]

Treatment for cysts depends on the size of the cyst and symptoms.

Pain caused by ovarian cysts may be treated with:

• Pain relievers, including acetaminophen/paracetamol (Tylenol or Panadol), nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin, Advil), or narcotic pain medicine (by prescription) may help reduce pelvic pain.^[9] NSAIDs usually work best when taken at the first signs of the pain.
• A warm bath, or heating pad, or hot water bottle applied to the lower abdomen near the ovaries can relax tense muscles and relieve cramping, lessen discomfort, and stimulate circulation and healing in the ovaries.^[10]
• Combined methods of hormonal contraception such as the combined oral contraceptive pill – the hormones in the pills may regulate the menstrual cycle, and prevent the formation of follicles that can turn into cysts.(American College of Obstetricians and Gynecologists, 1999c; Mayo Clinic, 2002e)^[9] However, a Cochrane review in 2011 concluded oral contraceptives are of no benefit in treating already present functional cysts.^[11]

Also, limiting strenuous activity may reduce the risk of cyst rupture or torsion.

Cysts that persist beyond two or three menstrual cycles, or occur in post-menopausal women, may indicate more serious disease and should be investigated throughultrasonography and laparoscopy, especially in cases where family members have had ovarian cancer. Such cysts may require surgical biopsy. Additionally, a blood test may be taken before surgery to check for elevated CA-125, a tumor marker, which is often found in increased levels in ovarian cancer, although it can also be elevated by other conditions resulting in a large number of false positives.^[12]

For more serious cases where cysts are large and persisting, doctors may suggest surgery. This may involve removing the cyst, or one or both ovaries.^[13] Features that may indicate the need for surgery include:^[14]

• Persistent complex ovarian cysts
• Persistent cysts that are causing symptoms
• Simple ovarian cysts larger than 5-10 centimeters
• Women who are menopausal or perimenopausal

Ovarian cyst rupture

A rupture of an ovarian cyst is usually a self-limiting, and only requires expectant management and analgesics. The main symptom is abdominal pain, but can also be asymptomatic. The pain may last from a few days to several weeks.^[15]