The ovaries produce the eggs in the female reproductive system. Eggs grow, develop, and mature in the ovaries and then are released during ovulation, part of the monthly menstrual cycle that occurs during the childbearing years. Ovarian cysts are fluid-filled sacs that form on the ovaries when the follicles (sacs) on the ovary that contain the egg mature, but do not release the egg into the fallopian tube where it would be fertilized.
A woman can develop one cyst or many cysts. Ovarian cysts can vary in size-from as small as a pea to as big as a grapefruit. Most cysts are small and do not cause symptoms. Some cysts might cause a dull ache in the abdomen because they are twisted, bleeding, or have burst; others might cause pain during sexual intercourse. Most cysts are benign (not cancerous). A few cysts, though, may turn out to be malignant (cancerous). For this reason, your doctor should check all cysts. If ovarian cysts are found early, many of the problems they cause can be treated.
There are different types of ovarian cysts:
These cysts are completely normal and form during ovulation. The follicles (sacs) on the ovary that contain the egg often do not mature, and become cysts. These cysts usually disappear during menstruation, before another menstrual cycle begins. If not, they will shrink in about one to three months. Your doctor may want to check in a few months to make sure the cyst has gotten smaller. Only women who are ovulating form functional cysts. If you are in menopause or past menopause and not having periods, you should not have functional cysts.
These cysts develop in women who have endometriosis, a condition in which tissue from the lining of the uterus (endometrium) grows in other areas, such as on the fallopian tubes, the ovaries, and on other organs outside of the uterus in the stomach. These may be filled with a thick, brown blood and so also are called "chocolate cysts." Because uterine tissue is sensitive to hormones, it bleeds monthly, which may cause it to form a growing cyst on the ovary. These cysts can be painful during sexual intercourse and during menstruation.
Benign cystic tumors (cystadenomas)
These tumors are non-cancerous and are often filled with a fatty liquid. They develop from cells on the outer surface of the ovary. Some of these tumors, called dermoid cysts, are lined with structures such as hair, or pieces of bone. They are often small and may not cause symptoms. They can, however, become large and uncomfortable.
Women who do not ovulate regularly can develop multiple cysts. This is a disorder in which the ovaries are enlarged and contain many small cysts. This can be caused by a condition called polycystic ovary syndrome (PCOS). Symptoms of PCOS include irregular menstrual periods, infertility, and increased body hair.