Ovarian cyst

An abnormal, fluid-filled swelling in an ovary. Ovarian cysts are common and, in most cases, noncancerous. The most common type, a follicular cyst, is one in which the egg-producing follicle enlarges and fills with fluid. Cysts may also occur in the corpus luteum, a mass of tissue that forms from the follicle after ovulation. Other types include dermoid cysts and cancerous cysts (see ovary, cancer of). Ovarian cysts are often symptomless, but some cause abdominal discomfort, pain during intercourse, or irregularities of menstruation such as amenorrhoea, menorrhagia, or dysmenorrhoea. Severe abdominal pain, nausea, and fever may develop if twisting or rupture of a cyst occurs. This condition requires surgery. An ovarian cyst may be discovered during a routine pelvic examination and its position and size confirmed by ultrasound or laparoscopy. In many cases, simple ovarian cysts – thin-walled or fluid-filled cysts – resolve themselves. However, complex cysts (such as dermoid cysts) usually require surgical removal. If an ovarian cyst is particularly large, the ovary may need to be removed (see oophorectomy).