Ovarian cysts are fluid-filled sacs similar to blisters that are situated within or on the surface of an ovary. Many women develop them during their reproductive years, and most women will have at least one during her life. While most ovarian cysts are harmless and present little to no discomfort, they can produce symptoms that can even be life threatening, especially if the cyst ruptures.

Often, women may not feel any symptoms from ovarian cysts, but in some cases they can experience symptoms similar to endometriosis, ectopic pregnancy, appendicitis or ovarian cancer. Menstrual irregularities, pelvic pain (during or before periods, during sexual intercourse or constant pain radiating to the back and thighs), nausea, breast tenderness, vomiting, and pressure on the bladder or rectum are some common symptoms. There are three types of ovarian cysts including follicular or functional ovarian cysts, corpus luteal ovarian cysts and endometrioma or chocolate cysts.

Endometriosis can cause complex ovarian cysts (endometriomas), commonly called chocolate cysts (because they are filled with a thick chocolate-colored material) that are usually sized between 0.4 in. (1.02 cm) and 4 in. (10.16 cm). 60% of women with endometriosis experience ovarian involvement. Small cysts are formed outside of the ovary, which enlarge and produce endometriosis of the ovary. Hormone stimulation during the menstrual cycle produces many small cysts that eventually occupy the normal ovarian tissue. They can rupture and eventually lead to severe pelvic pain.

Chocolate cysts and any other cysts can be dangerous, so it is important to contact a doctor as soon as possible if one of the more serious symptoms appears. It is always advisable to have a check-up once in a while.