Ovarian Cysts

Ovarian cysts are extremely common affecting almost every woman of childbearing age. They are fluid-filled sacs of variable sizes that develop in the ovary. Generally, there are 3 types of ovarian cysts including functional, endometriosis (chocolate) or neoblastic (tumorous) cysts.

Functional ovarian cysts

These are the commonest types of ovarian cysts. They usually form as a result of ovulation (egg release). Normally, the ovary contains many follicles (tiny cysts), each containing an egg. Every cycle, one of these follicles grows to reach a diameter of about 2 cm and then bursts to release the egg. After ovulation, the follicle changes to another smaller cyst called corpus luteum, which will gradually disappear. However, in some cases the follicle persists after ovulation and continues to grow reaching a size as big as an orange or even larger. This cyst usually secretes hormones (hence the name functional) and usually resolves with time, although this may take several months.

There are 2 types of functional cysts including simple cyst containing clear fluid and haemorrhagic cyst containing blood.

Chocolate cysts (endometriomas)

These cysts form as a result of endometriosis of the ovary. They contain old brownish blood, hence the name Chocolate. They vary in size from few mm to as large as an orange and can be either single or multiple. They are usually associated with other forms of endometriosis in the pelvis.

Neoblastic (tumorous) ovarian cysts:

There are many different types of tumours (growths) that can arise in the ovary. These tumours could either be cystic, solid or mixed (partly cystic and partly solid) in nature. They can be benign or malignant. Cystic tumours are usually benign and could resemble on ultrasound scan the appearance the functional cysts. Dermoid cysts are a common example of benign tumorous cysts, which are easily diagnosed by ultrasound scan. They usually contain different types of tissues such as bone, teeth, skin and hair. Malignant cysts usually have certain features that can be identified on ultrasound scan, although they can only be diagnosed by histological examination (i.e. examining the cells under the microscope).

What problems could cysts cause?

In many cases uncomplicated ovarian cysts are silent and cause no symptoms being only discovered during a routine ultrasound scan. Common symptoms of ovarian cysts include pelvic pain and swelling of the lower abdomen (in large cysts only). Mild to moderate pain usually results from slight bursting, twisting or bleeding of the cyst. Pressure symptoms similar to the fibroids could occur in women with very large cysts. In some cases, a sudden rupture (bursting), torsion or haemorrhage of the cyst could result in a sudden sharp pain in the lower abdomen that may be a medical emergency.

How can ovarian cysts be diagnosed?

Large cysts could be detected during internal examination, but smaller cysts will require an internal ultrasound scan. The scan is also helpful in determining the size, number and exact location of the cysts. It will also help to determine the nature of the cyst. However, the exact nature of the cyst could only be determined by histological examination of the cyst.

Another important test in women with ovarian cysts is to take a blood sample for the measurement of certain tumour markers (e.g. CA125) to distinguish between benign and malignant cysts.

How can ovarian cysts be treated?

Silent simple cysts, which are not larger than 5 cm, could be watched by repeated scans every 2-3 months until they resolve. If the cyst is symptomatic or not resolving with time, it should be removed surgically. The preferred approach for this procedure is keyhole surgery. Women with very large cysts should be warned that the ovary might be removed during the surgical removal of the cyst.