An ovarian cyst happens when fluid accumulates within a thin membrane inside the ovary. The size can range from as small as a pea to larger than an orange.
A cyst is a closed sac-like structure. It is divided from surrounding tissue by a membrane. It is an abnormal pocket of fluid, similar to a blister. It contains either liquid, gaseous, or semi-solid material. The outer or capsular portion of a cyst is called the cyst wall.
It is different from an abscess because it is not filled with pus. A pus-filled sac is an abscess.
Most ovarian cysts are small and harmless. They occur most frequently during the reproductive years, but they can appear at any age.
There are often no signs or symptoms, but ovarian cysts can sometimes cause pain and bleeding. If the cyst is over 5 centimeters in diameter, it may need to be surgically removed.
There are two main types of ovarian cysts:
- Functional ovarian cysts – the most common type. These harmless cysts form part of the female’s normal menstrual cycle and are short-lived.
- Pathological cysts – these are cysts that grow in the ovaries; they may be harmless or cancerous (malignant).
The causes are different for each type. We will look at each type in turn.
Functional ovarian cysts
There are two types of functional ovarian cysts:
1) Follicular cysts
Follicular cysts are the most common type. A woman has two ovaries. The egg moves from an ovary into the womb, where it can be fertilized by sperm. The egg is formed in the follicle, which contains fluid to protect the growing egg. When the egg is released, the follicle bursts.
In some cases, the follicle either does not shed its fluid and shrink after releasing the egg, or it does not release an egg. The follicle swells with fluid, becoming a follicular ovarian cyst.
One cyst normally appears at any single time, and it normally goes away within a few weeks.
2) Luteal ovarian cysts
These are less common. After the egg has been released, it leaves tissue behind, known as the corpus luteum. Luteal cysts can develop when the corpus luteum fills with blood. This type of cyst normally goes away within a few months. However, it may sometimes split, or rupture, causing sudden pain and internal bleeding.
There are two types of pathological cysts:
1) Dermoid cysts (cystic teratomas)
A dermoid cyst is usually benign. They are formed from the cells that make eggs. These cysts need to be removed surgically. Dermoid cysts are the most common type of pathological cyst for women under 30 years of age.
Cystadenomas are ovarian cysts that develop from cells that cover the outer part of the ovary. Some are filled with a thick, mucus-like substance, while others contain a watery liquid.
Rather than growing inside the ovary, cystadenomas are usually attached to the ovary by a stalk. By existing outside the ovary, they can grow quite large. They are rarely cancerous, but they need to be removed surgically.
Cystadenomas are more common among women aged over 40 years.
Most cysts are symptomless. If symptoms are present, they are not always useful for diagnosing an ovarian cyst, because other conditions, such as endometriosis, have similar symptoms.
Symptoms of an ovarian cyst may include:
- Irregular and possibly painful menstruation: It may be heavier or lighter than before.
- Pain in the pelvis: This may be a persistent pain or an intermittent dull ache that spreads to the lower back and thighs. It may appear just before menstruation begins or ends.
- Dyspareunia: This is pelvic pain that occurs during sexual intercourse. Some women might experience pain and discomfort in the abdomen after sex.
- Bowel issues: These include pain when passing a stool, pressure on the bowels or a frequent need to pass a stool.
- Abdominal issues: There may be bloating, swelling, or heaviness in the abdomen.
- Urinary issues: The woman may have problems emptying the bladder fully or she may or feeling the need to urinate frequently.
- Hormonal abnormalities: Rarely, the body produces abnormal amounts of hormones, resulting in changes in the way the breasts and body hair grow.
Some symptoms may resemble those of pregnancy, for example, breast tenderness and nausea.
An ovarian cyst often causes no problems, but sometimes it can lead to complications.
- Torsion: The stem of an ovary can become twisted if the cyst is growing on it. It can block the blood supply to the cyst and cause severe pain in the lower abdomen.
- Burst cyst: If a cyst bursts, the patient will experience severe pain in the lower abdomen. If the cyst is infected, pain will be worse. There may also be bleeding. Symptoms may resemble those of appendicitis or diverticulitis.
- Cancer: In rare cases, a cyst may be an early form of ovarian cancer.
Treatment will depend on:
- the person’s age
- whether they have undergone menopause or not
- the size and appearance of the cyst
- whether there are any symptoms
Watchful waiting (observation)
Sometimes watchful waiting is recommended, especially if the cyst is a small, functional cyst (2 to 5 centimeters) and the woman has not yet undergone menopause
An ultrasound scan will check the cyst a month or so later, to see whether it has gone
Birth control pills
To reduce the risk of new cysts developing in future menstrual cycles, the doctor may recommend birth control pills. Oral contraceptives may also reduce the risk of developing ovarian cancer.
Surgery may be recommended if:
- there are symptoms
- the cyst is large or appears to be growing
- the cyst does not look like a functional cyst
- the cyst persists through 2 to 3 menstrual cycles.
Two types of surgery are:
- Laparoscopy, or keyhole surgery: The surgeon uses very small tools, to remove the cyst through a small incision. In most cases, the patient can go home the same day. This type of surgery does not usually affect fertility, and recovery times are fast.
- Laparotomy: This may be recommended if the cyst is cancerous. A longer cut is made across the top of the pubic hairline. The cyst is removed and sent to the lab for testing. The patient usually stays in the hospital for at least 2 days.
If the cyst may be cancerous, a biopsy can be taken for testing.
If the result shows that cancer is present, more organs and tissue may need to be removed, such as the ovaries and uterus.
Most ovarian cysts present no signs or symptoms, so they often remain undiagnosed.
Sometimes a cyst that does not produce symptoms may be diagnosed during an unrelated pelvic examination or ultrasound scan.
Diagnosis aims to assess the shape, size, and composition of the cyst, whether it is filled with solid or liquid.
Diagnostic tests may include:
- an ultrasound scan
- a blood test
- a pregnancy test
There is no way to prevent ovarian cyst growth.
However, regular pelvic examinations will allow for early treatment if needed. This can often prevent complications.