Ovarian cysts are fluid-filled sacs that grow within or on the surface of the ovary. Most women will develop cysts as part of the normal changes in their menstrual cycle. These are known as functional cysts. They are usually small and painless and disappear on their own without the need for medical attention. They can last for two or three menstrual cycles.
Some women may have pathological cysts which are tumours in the ovaries that are either benign (harmless) or malignant (cancerous). These type of cysts are less common and form as a result of abnormal cell growth, rather than as part of the normal function of the menstrual cycle. Benign cysts include dermoid cysts, cystadenomas and endometriomas.
Dermoid cysts are the most common type of pathological cysts. They develop from embryological cells that become eggs in the ovary. Dermoid cysts can grow to a large size and there is a risk of torsion (twisting) of the cyst which may result in severe pain and damage to the remaining healthy ovarian tissue. They are therefore best removed surgically.
Cystadenomas develop from cells that cover the outer layer of the ovary. They are either filled with a watery liquid or with a thicker, mucous substance. They are typically attached to the ovaries by a stalk and can grow to a very large size. Most are benign, although they should still be surgically removed to confirm the diagnosis. As with dermoids, cystadenomas can also cause ovarian torsion.
Endometriomas, also known as chocolate cysts, are blood-filled cysts on the ovary which develop as a result of endometriosis. This is a condition in which endometrial tissue grows outside the uterus causing scarring and formation of cysts on the ovaries. They are usually associated with painful periods and pain with intercourse (dyspareunia). Laparoscopic removal of the cyst is often necessary.
The majority of ovarian cysts are small and do not cause problems. However, they may cause problems if they rupture or cause torsion. Symptoms may include:
- pain and discomfort in the abdomen/pelvis
- painful intercourse
- abdominal swelling or a bloating feeling
- abnormal bleeding or irregular periods
- changes in bladder or bowel habits
- difficulty falling pregnant
An ultrasound scan is most commonly used to check for ovarian cysts. Occasionally laparoscopy is necessary.
Since most ovarian cysts show no symptoms or signs, they often go undiagnosed. Most are found during unrelated routine pelvic examinations or ultrasounds. However, if a woman is experiencing any symptoms of ovarian cysts, an examination and diagnosis can be made in several ways.
Ultrasound scans are commonly used to confirm the presence of pelvic cysts. This usually involves using a vaginal and abdominal probe. The scan can also help as a guide to the location, complexity and the nature of the cyst. If a cyst is found during the ultrasound, a repeat scan after a few months is recommended to monitor any change in the cyst. If the ultrasound is arranged by a GP or other specialist, a referral to a gynaecologist may be advised.
CT or MRI scans
A CT or MRI scan may sometimes be necessary if an ultrasound fails to locate or identify the cyst. CT scans use body-imaging devices to create cross-sectional images of the internal organs. MRI scans use magnetic waves to produce detailed images of internal organs.
Tumour markers blood test
If there is a concern with an ovarian cyst then a blood test for tumour markers such as CA 125 may need to be obtained. A significant rise in the CA125 may suggest the tumour is cancerous. However, elevated CA125 levels can also occur in non-cancerous conditions, such as endometriosis, uterine fibroids and pelvic inflammatory disease.
The treatment options will vary depending on symptoms, the size and appearance of the cyst and also the age of the patient. Most ovarian cysts will disappear after a few months without treatment.
If the cyst is large or is causing problems, or if the doctor thinks it might be cancerous, it can be removed surgically.
Possible treatments include:
Wait and see
If the cyst is small and asymptomatic, it may be best to monitor its development with a further ultrasound scan and a repeat tumour marker blood test after three or four months. If the cyst has increased in size or become symptomatic then surgical intervention may be required.
Certain types of cyst (functional cysts) are caused by the ovulation process, so by using treatments such as a combined contraceptive pill, ovulation can be stopped and the formation of these types of cysts reduced.
If the cyst is large or symptomatic then surgical intervention may be advised. Even when a large cyst is not causing problems, surgical removal is sometimes advised so that its nature can be analysed in a laboratory.