An ovarian cyst is a fluid-filled sac or pouch located on or inside the ovary. They can occur at any age but are most commonly found during the childbearing years. Ovarian cysts are very common and may be normal (functional cysts) or abnormal. Functional (normal) ovarian cysts are cysts formed during a woman’s normal monthly ovarian cycle (e.g. mature egg or an ovulation cyst). This means that most woman will develop a small cyst-like structure (called follicles) at some stage during her monthly cycle. These cysts are always benign (not cancer) and will disappear on their own without any treatment.
Most of the abnormal ovarian cysts are also benign growths, but they are tumour-like and will therefore not disappear on their own. Although rare, some of these (abnormal) cysts may be cancerous in nature. The main concern is to identify these cancers from amongst all the other types of cysts.
What are the different types of ovarian cysts?
- Functional cyst -This is the most common type of ovarian cyst. It usually causes no symptoms. Functional cysts often go away without treatment within 6–8 weeks.
- Teratoma – This type of cyst contains different kinds of tissues that make up the human body, such as skin, hair, cartilage, bone, etc. These cysts may be present from birth but can grow during a woman’s reproductive years. In very rare cases, some teratomas may be cancerous.
- Cystadenoma -These cysts form on the outer surface of the ovary. They can grow very large and usually are benign. Rarely a malignant variant is also encountered.
- Endometrioma – This cyst forms as a result of endometriosis.
What are the symptoms of ovarian cysts?
In most cases, cysts do not cause any symptoms. Many are found during a routine pelvic exam or imaging test done for another reason. Some cysts may produce abdominal or pelvic pain or pain on intercourse. The symptoms are variable and do not always correspond to the severity of the disease. Both normal and abnormal ovarian cysts can produce symptoms, usually in relation to a complication of the cyst, such as:
- Torsion – Larger cysts may cause twisting of the ovary (and associated blood supply). This twisting usually causes a sudden and acute pain (on one side of the abdomen) and is often associated with nausea and vomiting.
- Rupture – Cysts may burst and spill their contents into the abdomen. Depending on the content of the cyst, this may cause pain or other complications.
- Haemorrhage – Bleeding may occur into the cyst and produce pain.
- Pressure symptoms – Large ovarian cysts can cause compression of other abdominal and pelvic organs and produce symptoms e.g. the need to pass urine more frequently.
How are ovarian cysts diagnosed?
If your gynaecologist suspects that you may have a cyst, the following tests may be recommended to get more information:
- Ultrasound exam – This test uses sound waves to create pictures of the internal organs. An instrument called a transducer is placed in the vagina or on the abdomen. The views created by the sound waves show the shape, size, and location of the cyst. The views also show whether the cyst is solid or filled with fluid.
- Blood tests – You may have a blood test that measures the level of a substance (tumour-marker) called CA-125. An increased level of CA-125, along with certain findings from ultrasound and physical exams, may raise concern for ovarian cancer, especially in a woman who is past the menopause. Several other blood tests can also be used to help identify whether a mass on the ovary is concerning for ovarian cancer.
How are ovarian cysts treated?
There are several treatment options for cysts. Choosing an option depends on the type of cyst and other factors. Treatment options include watchful waiting and, if the cyst is large or causing symptoms, surgery.
What is watchful waiting?
Watchful waiting is a way of monitoring a cyst with repeat ultrasound exams to see if the cyst has changed in size or appearance. Your gynaecologist will decide when to repeat the ultrasound exam and how long this follow-up should last. Many cysts go away on their own after one or two menstrual cycles.
When is surgery recommended?
Surgery is recommended if a cyst is very large, causing symptoms or if a cancer is suspected. The type of surgery depends on several factors, including the size of the cyst, the age of the patient, the desire to have more children, and whether you have a family history of ovarian or breast cancer.
A cystectomy is an operation where the whole cyst is removed but the remainder of the ovary is left in place. The procedure is normally performed under a general anaesthetic in the operating theatre. The abdomen and pelvis are systematically evaluated and the cyst is peeled off the ovary. All ovarian cysts are sent to the laboratory for testing. You will be informed of the results of these tests during your follow-up appointment. On occasion, further surgery may be recommended if there are suspicious features seen on these laboratory results. It is a futile exercise to only drain a cyst or remove part of a cyst as this cyst will most certainly recur in future. In some cases, the entire ovary may need to be removed. This is called an oophorectomy.
How is surgery performed?
If your cyst is thought to be benign, minimally invasive (key-hole) surgery is recommended. Minimally invasive surgery is done using small incisions and a special instrument called a laparoscope. This type of surgery is called a laparoscopy (see section on laparoscopy). Nowadays the majority of surgeries for ovarian cysts are performed via this route.
Open surgery (where a large incision is made horizontally or vertically in the lower abdomen) should be reserved for cases where ovarian cancer is suspected.
What happens after this procedure?
Usually, the ovary resumes normal function if a cystectomy has been performed. In certain cases, however, the ovary may not recover, failing to produce hormones and release eggs. Provided the other ovary is working, this is of little consequence and you will continue to have your periods at your normal interval. If you still want to become pregnant and need infertility treatment, a cystectomy may decrease the amount of usable eggs (of the affected ovary) dramatically and therefore may decrease your chances to get pregnant.