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Ovarian cyst

 

An ovarian cyst is a fluid-filled sac that develops on a woman's ovary. Ovarian cysts are very common and they do not usually cause any symptoms.

In most cases, they are harmless and usually disappear without the need for treatment.

However, if the cyst is large or is causing symptoms, it will probably have to be surgically removed. See ovarian cysts - treatment for more information.

Ovarian cysts can affect women of any age.

The ovaries

The ovaries are two small, bean-shaped organs that are part of the female reproductive system.
Every woman has a pair of ovaries that sit either side of the womb (uterus).

The ovaries have two main functions:

  • they release an egg approximately every 28 days as part of the menstrual cycle
  • they release the female sex hormones, oestrogen and progesterone, which play an important role in female reproduction

Types of ovarian cyst

There are two main types of ovarian cyst:

  • Functional ovarian cyst - (the most common type). These are harmless cysts that are short- lived and formed as part of the menstrual cycle.
  • Pathological ovarian cyst - these are much less common and occur as the result of abnormal cell growth (most pathological ovarian cysts are not cancerous).

See ovarian cysts - causes for more information about the different types of ovarian cyst.

How common are ovarian cysts?

Ovarian cysts are very common. It is estimated that virtually all women who still have a monthly period, and 1 in 5 women who have been through the menopause, will have one or more ovarian cysts.

Ovarian cysts that cause symptoms are much less common, affecting only 1 in every 25 women at some point in their life.

Fertility

Ovarian cysts usually do not affect a woman's ability to conceive.

Even if the cyst is larger and needs to be removed, this is usually done using laparoscopy, which preserves a woman's fertility.

Reduced breast cancer risk

Having an ovarian cyst can be upsetting, particularly if it is causing symptoms.

The good news is that researchers have found that women (particularly in black women) with ovarian cysts have a lower risk of developing breast cancer. The reasons for this are unclear.

An ovarian cyst will usually only cause symptoms if:

  • it ruptures (splits)
  • it is very large
  • it blocks the blood supply to the ovaries (torsion)

Under such circumstances, you may have the following symptoms:

  • pelvic pain, which can range from a dull heavy sensation (associated with large cysts) to a sudden, sharp pain (which is associated with a ruptured cyst or torsion)
  • difficulty emptying your bowels
  • pelvic pain during sexual intercourse
  • a frequent need to urinate
  • changes to your normal menstruation - you may develop irregular periods, heavy periods or lighter periods than usual
  • a feeling of fullness and bloating
  • indigestion or feeling very full even though you have only eaten a little

When to seek medical advice

You should contact your GP if you feel persistent pelvic pain and/or notice a change in your normal menstrual cycle.

A sudden, sharp pelvic pain could be caused by an ovarian cyst rupturing (bursting) or blocking the blood supply to your ovaries.

In such circumstances, contact your GP immediately. If this is not possible, telephone your local GP out-of -hours service

Benign
Benign refers to a condition that should not become life-threatening. In relation to tumours, benign means not cancerous.
Bladder
The bladder is a small organ near the pelvis that holds urine until it is ready to be passed from the body.
Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Cysts
A cyst is a fluid-filled sac or cavity in the body.
Ovary
Ovaries are the pair of reproductive organs that produce eggs and sex hormones in females.
Pain
Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.
Womb
The uterus (also known as the womb) is a hollow, pear-shaped organ in a woman where a baby grows during pregnancy.

There are several different kinds of ovarian cyst, which are categorised as either:

  • functional cysts (the most common type): harmless cysts that form as part of the menstrual cycle
  • pathological cysts: tumours in the ovaries that are either benign (harmless) or malignant (cancerous)

Functional cysts

There are two types of functional ovarian cyst:

  • follicular cyst
  • luteal cyst

These are described below.

Follicular cysts

Follicular cysts are the most commonly seen ovarian cysts.

The ovaries are two small, bean-shaped organs that are part of the female reproductive system. They release an egg every month which moves into the womb (uterus) where it is fertilised by a man's sperm.

Each egg forms in a tiny structure inside the ovary called a follicle. The follicle contains fluid to protect the egg as it grows and it bursts when the egg is released.

However, sometimes a follicle does not release an egg, or it does not shed its fluid and shrink after the egg is released. If this happens, the follicle can get bigger as it swells with fluid. The fluid-filled follicle becomes a follicular ovarian cyst.

Usually, only one cyst appears at a time and it will often disappear without treatment after a few weeks.

Luteal cysts

Luteal cysts are less common than follicular cysts. They develop when the tissue that is left behind after an egg has been released, known as the corpus luteum, fills with blood.

Luteal cysts usually disappear on their own within a few months, but they can sometimes rupture (burst), causing internal bleeding and sudden pain.

Pathological cysts

A dermoid cyst, is the most common type of pathological cyst in women who are under 40 years old.

In women over 40 years of age, a cystadenoma is the most common type.

Dermoid cysts

Dermoid cysts develop from the cells that are used to create eggs. As eggs have the ability to create any type of cells, dermoid cysts can consist of a wide range of different types of human tissue, including blood, fat, bone and hair.

Dermoid cysts have the potential to grow very large. They can sometimes grow up to 15cm (6 inches) in diameter. They are not usually cancerous, but will usually need to be surgically removed.

Cystadenomas

Cystadenomas develop from cells that cover the outer part of the ovary. There are two main types of cystadenomas:

  • serous cystadenomas
  • mucinous cystadenomas

Serous cystadenomas do not usually grow very large but they can cause symptoms if they rupture.

In contrast, mucinous cystadenomas can grow very large (up to 30cm or 12 inches), filling up the inside of the abdomen and placing pressure on other organs, such as the bladder and bowel.

This can result in symptoms such as:

  • indigestion
  • a frequent need to urinate

Larger mucinous cystadenomas carry the risk of rupturing, or blocking the blood supply to the ovaries (torsion). As with dermoid cysts, mucinous cystadenomas are rarely cancerous. 

Conditions that cause ovarian cysts

Endometriosis

If you have endometriosis, you may develop ovarian cysts. Endometriosis occurs when pieces of the tissue that lines the womb (the endometrium) are found outside the womb in areas such as the fallopian tubes, ovaries, bladder, bowel, vagina or rectum. Sometimes, blood-filled cysts can form in this tissue.

See the Health A-Z topic about endometriosis for more information.

Polycystic ovarian syndrome

Polycystic ovarian syndrome is a condition that causes lots of small, harmless cysts to develop on your ovaries. The cysts develop if there is a problem with the balance of hormones that are produced by the ovaries.

See the Health A-Z topic about polycystic ovarian syndrome for more information.

Benign
Benign refers to a condition that should not become life-threatening. In relation to tumours, benign means not cancerous.
Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Cysts
A cyst is a fluid-filled sac or cavity in the body.
Ovaries
Ovaries are the pair of reproductive organs that produce eggs and sex hormones in females.
Pain
Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.
Rupture
A rupture is a break or tear in an organ or tissue.
Tissue
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.  
Uterus
The uterus (also known as the womb) is a hollow, pear-shaped organ in a woman where a baby grows during pregnancy.

Most ovarian cysts do not cause any symptoms, therefore they often go undiagnosed. Sometimes, ovarian cysts are diagnosed by chance - for example, during a pelvic examination. They can also be spotted when people have an ultrasound scan for an unrelated reason.

If you have symptoms that could be caused by an ovarian cyst, your GP will probably refer you to a gynaecologist (a doctor who specialises in female reproductive health). The gynaecologist will carry out a vaginal examination to see whether they can feel any abnormal swelling.

Ultrasound scan

To confirm an ovarian cyst, you usually need to have an ultrasound scan. An ultrasound scanner works by using sound waves to build up an image of the inside of your body.

The probe of the scanner is placed on your abdomen to scan your ovaries. The doctor may also put a small, tube-shaped probe inside your vagina to scan your ovaries from this angle. An ultrasound scan can usually confirm whether you have an ovarian cyst and how big it is.

Blood test

Your GP may refer you for a blood test if an ultrasound scan shows that the cyst is partially solid, as opposed to being filled with fluid. The blood test will be used to measure levels of a protein called CA125, which is often elevated in cases of ovarian cancer.

If your blood test shows a higher than normal level of CA125, it does not automatically mean that you have ovarian cancer because levels can fluctuate from person to person.

See ovarian cancer - diagnosis for more information.

Blood test
During a blood test, a sample of blood is taken from a vein using a needle so it can be examined in a laboratory.
Cyst
A cyst is a fluid-filled sac or cavity in the body.
MRI
MRI stands for magnetic resonance imaging. It is the use of magnets and radio waves to take detailed pictures of inside the body.
Ovaries
Ovaries are the pair of reproductive organs that produce eggs and sex hormones in females.
Swelling
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
Ultrasound scan
Ultrasound scans are a way of producing pictures of the inside the body using sound waves.

If you have an ovarian cyst, whether it needs to be treated will depend on:

  • its appearance and size
  • whether you have any symptoms
  • whether you have had the menopause (post-menopausal women have a slightly higher risk of developing ovarian cancer)

Watchful waiting

In the majority of cases, a policy of 'watchful waiting' will be recommended where you receive no immediate treatment. This is because most cysts will disappear after a few weeks without the need for treatment. A follow-up ultrasound scan will usually confirm that this is the case.

Due to the slightly higher risk of ovarian cancer in women who have experienced the menopause, regular ultrasound scans and blood tests are usually recommended until the cyst disappears. In addition, post-menopausal women are advised to have a follow-up ultrasound scan four months after the cysts have gone.

Surgery

If the cyst is large, or if it is causing symptoms, it will probably need to be removed. Doctors sometimes recommend removing the cyst even if it is not causing symptoms. This is because it is not always possible to tell what type of cyst it is without looking at it under a microscope. Removing it also reduces the risk of the cyst becoming cancerous later on.

There are two types of operation, which are usually carried out under general anaesthetic (you will be asleep during the operation and will feel no pain). They are:

  • laparoscopy
  • laparotomy

Both procedures are described below.

Laparoscopy

Smaller cysts can sometimes be removed using a surgical technique called a laparoscopy. This is a type of keyhole surgery where small cuts are made in your lower abdomen and gas is blown into the pelvis to lift the wall of the abdomen away from the organs inside.

A laparoscope, which is a small, tube-shaped microscope with a light on the end, is passed into your abdomen so that the surgeon can see your internal organs. Using tiny surgical tools, the surgeon will be able to remove the cyst through the small cut in your skin.

After the procedure, the cuts are closed using dissolvable stitches. The operation takes about half an hour to perform, depending on the size and type of cyst. Most women can go home on the same day as the operation.

A laparoscopy is the preferred approach because it causes less pain, helps to preserve fertility and lets you resume normal activity sooner.

Laparotomy

If there is a risk that the cyst is cancerous, a more invasive procedure called a laparotomy may be recommended.

During a laparotomy, a larger cut is made to give the surgeon better access to the cyst. The whole cyst and ovary is removed and sent to a laboratory to check whether it is cancerous. The skin is then closed using stitches. You may have to stay in hospital overnight or for a few days.

If only one of your ovaries is removed, your remaining ovary will still release hormones and eggs as normal, so your health and fertility should be unaffected.

If both ovaries needed to be removed then this would trigger an early menopause (if you had not already gone through the menopause).

However, it may still be possible to have a baby by having a donated egg implanted into your womb.

Treatment for cancer

If the cyst is found to be cancerous, you may need to have treatment to remove both of your ovaries, your womb (uterus) and some of the surrounding tissue.

This would trigger an early menopause and mean that you would be infertile.

See ovarian cancer - treatment for more information

Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Cyst
A cyst is a fluid-filled sac or cavity in the body.
Lymph nodes
Lymph nodes are small oval tissues that remove unwanted bacteria and particles from the body. They are part of the immune system.
Ovaries
Ovaries are the pair of reproductive organs that produce eggs and sex hormones in females. 
Tissue
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.  
Ultrasound scans
Ultrasound scans are a way of producing pictures of inside the body using sound waves.
Uterus
The uterus (also known as the womb) is a hollow, pear-shaped organ in a woman where a baby grows during pregnancy. 

Recovering from surgery

After surgery to remove some or all of an ovarian cyst, you will feel some pain in your abdomen. However, this usually improves after about 48 hours.

Contact your GP if you notice any of the following symptoms:

  • heavy bleeding
  • severe pain or swelling in your abdomen
  • high temperature (fever) of 38ºC (100.4ºF) or above
  • dark or smelly vaginal discharge

These symptoms may indicate an infection.


Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.