To understand ovarian cyst, one should know the basic function of the ovaries which are two small organs in the lower abdomen holding eggs. The eggs grow, develop, and mature in the ovaries and they are released during ovulation in the middle of the normal menstrual cycle.
Ovarian cysts are fluid-filled sacs that form in the ovaries when the follicles (sacs) that contain the egg do not release it during ovulation. A woman can develop one or more cysts which can vary in size from a small blister to as big as water-melon.
Types of Ovarian Cysts
- Functional cysts: These are commonly seen in young women of childbearing age. The follicles (sacs) containing the egg do not mature and become cysts. They usually disappear during menstruation. It is important that cysts should be checked by ultrasound scan (sonogram) during or when the menstrual period is just over. If you are menopause or past menopause, you should not have functional cysts.
- Endometriotic cysts (blood cysts): These cysts are also called chocolate cysts because of its contents of thick old clotted blood. They developed in women with endometriosis and can be considered as a severe stage of the disease. They can grow with time and cause severe abdominal cramps during menstruation and painful sexual intercourse. Occasionally, it may burst (i.e. rupture) mimicking appendicitis and requiring emergency operation. Very rarely, it may become cancerous.
- Dermoid cysts (hairy cysts): These cysts are usually not cancerous (i.e. benign). They are often filled with fatty cheesy contents with hairs and teeth and bones. They are often small and may not cause symptoms. When they become large they can cause complications (see below).
- Serous cysts (watery cysts): These cysts contain yellow fluid and can become cancerous.
- Mucinous cysts (jelly cysts): These cysts contain mucus-like or jelly type of contents and can turn cancerous.
Functional cysts, dermoid, serous and mucinous cysts are usually without symptoms. However, when they become larger, they can cause a dull ache of a filling of fullness (bloatedness) in the lower abdomen (belly) or back. They may also press on the bladder causing frequent urination or difficulty in passing urine. Sometimes, they may develop complications such as getting twisted/infected, bleeding into the cyst, or breaks open (rupture). These can cause nausea, vomiting, fever, and severe abdominal pain requiring immediate operation to remove the cysts. Occasionally the cysts may turn cancerous. Ovarian cancer usually does not have any symptoms in the early stage. There may be non-specific symptoms such as loss of appetite, loss of weight and bloated feeling of the abdomen. In the late stage, there may be swelling of the abdomen with fluid and swelling of legs and feet.
Endometriotic cysts, on the other hand, are usually symptomatic (see endometriosis).
Diagnosis and Treatment
Some of the ovarian cysts are found during the annual check-up by pelvic examination. Some of them are discovered by ultrasound examination (ultrasound scan). Dermoid cysts are occasionally detected by X-ray of the abdomen because of the teeth or bones they contain.
Once the cyst is found, the gynaecologist may want to perform the ultrasound scan to see whether it contains only fluid or fluid mixes with solid – an indication that the cyst may be cancerous. The location and size of the cyst will be noted. The doctor may decide to "wait and see" and repeat the scan during or soon after the period. If it is a functional cyst, it will shrink or disappear. If the cyst persists or becomes painful, a blood test called CA125 may be performed. This test is to detect a protein substance in the blood of women with ovarian cancer (tumour marker test). However, this test is not specific as patients with non-cancerous conditions such as endometriosis and pelvic infection may also have substance positive result in the blood.
If the cyst appears benign (non-cancerous) on ultrasound and CA125 is normal, laparoscopic removal (key-hole surgery) may be done (see laparoscopy).
If the cyst is too large, it may be removed by the conventional way called laparotomy. Under general anaesthesia, an incision is made in the abdomen. The cyst is then removed and could be sent for frozen section (a microscopic test in the operation room) to find out whether the cyst is cancerous or not. If it is not cancerous, the cyst is then removed and the ovary is then restored by proper suturing. If it is cancerous, a more extensive operation involving removal of the womb may be performed.