Ovarian Cysts

The ovary is one of a pair of reproductive glands in women that are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of an almond. The ovaries produce eggs (ova) and female hormones. The ovaries are the main source of female hormones, which control the development of female body characteristics such as the breasts, body shape, and body hair. They also regulate the menstrual cycle and pregnancy. Ovarian cysts are closed, sac-like structures within an ovary that contain a liquid, gaseous, or semisolid substance. The ovary is also referred to as the female gonad.

Ovarian cysts form for numerous reasons. The most common type is a follicular cyst, which results from the growth of a follicle. A follicle is the normal fluid-filled sac that contains an egg. Follicular cysts form when the follicle grows larger than normal during the menstrual cycle and does not open to release the egg. Usually, follicular cysts resolve spontaneously over the course of days to months. Cysts can contain blood (hemorrhagic cysts) from injury or leakage of tiny blood vessels into the egg sac.

Another type of ovarian cyst that is related to the menstrual cycle is a corpus luteum cyst. The corpus luteum is an area of tissue within the ovary that occurs after an egg has been released from a follicle. If a pregnancy doesn't occur, the corpus luteum usually breaks down and disappears. It may, however, fill with fluid or blood and persist as a cyst on the ovary. Usually, this cyst is found on only one side and produces no symptoms.

Occasionally, the tissues of the ovary develop abnormally to form other body tissues such as hair or teeth. Cysts with these abnormal tissues are called benign cystic teratomas or dermoid cysts.

Endometriosis is a condition in which cells that normally grow inside the uterus (womb), instead grow outside of the uterus. The ovary is a common site for endometriosis. When endometriosis involves the ovary, the area of endometrial tissue may grow and bleed over time, forming a brown-colored cystic area sometimes referred to as a chocolate cyst or endometrioma.

Both benign and malignant tumors of the ovary may also contain cysts. Furthermore, the condition known as polycystic ovarian syndrome (PCOS) is characterized by the presence of multiple cysts within both ovaries. PCOS is associated with a number of hormonal problems and is the most common cause of infertility in women.

Infections of the pelvic organs can involve the ovaries and Fallopian tubes. In severe cases, pus-filled cystic spaces may be present on or around the ovary or tubes. These are known as tubo-ovarian abscesses.

Source: MedicineNet.com
http://www.medicinenet.com/ovarian_cysts/article.htm