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Medical Description

OvariesThe ovaries are two almond-shaped organs in a woman's pelvis. At the beginning of a woman's life, the ovaries contain millions of eggs (called ova).

During a woman’s reproductive years, an egg matures each month and travels down through one of the fallopian tubes to the uterus. If it unites with a man's sperm and becomes fertilized, the woman becomes pregnant; otherwise, the unfertilized egg is discarded during a woman's period.

Types of Cysts

Functional ovarian cystsFunctional ovarian cysts
Functional ovarian cysts are the most common kind of ovarian cyst. These occur when there is a disruption in the normal monthly development and release of an egg. Normally, an egg matures in a fluid-filled sac (a follicle) in the ovary. If the egg is not released properly or if this sac fills with fluid after the egg is released, a functional cyst forms. Most women have a functional cyst occasionally, but are rarely aware of them. Our bodies usually reabsorb these cysts within a few months, but a small proportion of cysts will cause pelvic pain and may require treatment.

Hemorrhagic cysts
If a tiny tear occurs in the ovary, the egg sac or surrounding tissues may fill with blood. This is called a hemorrhagic cyst and is also usually reabsorbed within a few months.

If tiny multiple functional cysts appear in the ovaries, this may be a sign of polycystic ovary syndrome.

Dermoid cysts
Dermoid cysts form from the egg cells within the ovary. Because eggs have the potential to form all kinds of human cells, a dermoid cyst can contain a bizarre combination of different kinds of tissue, including skin, bone and hair cells. Dermoid cysts are more likely to cause complications than functional cysts, and often need to be removed. However, fewer than 2 percent are malignant (cancerous).

A cystadenoma is a cyst formed from the cells of the outer lining of the ovary. A cystadenoma has some characteristics of a cyst and some of a tumour. Approximately one cystadenoma in eight is cancerous. Malignant cystadenomas are uncommon in pre-menopausal women.

Endometriomas are cysts in the ovaries, which are made up of endometrial tissue (cells from the lining of the uterus). This is a form of endometriosis.

Complications Associated with Ovarian Cysts

Ovarian cysts rarely cause complications, but when they do, they may be painful and need to be removed. If an ovarian cyst breaks (ruptures) and releases fluid, it is more likely to cause pain and pressure.

A large, heavy cyst can cause the ovary to twist and cut off its blood supply. This is called torsion. It is usually very painful and requires emergency surgery to save the ovary. Torsion is more likely with the rarer forms of ovarian cysts, such as dermoid cysts.

Ovarian Cysts and Cancer

Functional cysts are almost never malignant, especially when they are discovered prior to menopause. Doctors can usually distinguish a simple ovarian cyst from a cancerous growth by looking at the ultrasound images. There is no evidence to suggest that women who are prone to developing ovarian cysts are any more likely to get cancer than other women are.

After menopause, the risk of ovarian cancer increases. If you have gone through menopause, your doctor may suggest removing the cyst. In most cases, even when a cyst is removed from a post-menopausal woman, it is not cancerous. The removal is done as a precaution because age is the clearest risk factor for ovarian cancer.


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Ovarian Cysts

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