An ovarian cyst is a sac filled with fluid or a semisolid material that develops on or within an ovary.

Typically, ovarian cysts are functional (not disease related) and occur as a normal process of ovulation. During the days before ovulation, a follicle grows. But at the time of expected ovulation, the follicle fails to break open and release an egg, as it is supposed to. Instead, the fluid within the follicle remains and forms a cyst.

Functional, or physiological, ovarian cysts usually disappear within 8 - 12 weeks without treatment. They are relatively common, and are more common during a woman's childbearing years (puberty to menopause). Ovarian cysts are rare after menopause.

No known risk factors have been identified.

Functional ovarian cysts are not the same as ovarian tumors (including ovarian cancer) or cysts due to hormone-related conditions such as polycystic ovarian disease. Some non-functional ovarian cysts must be treated to go away.

An ovarian cyst can cause pain if it pushes on nearby structures, ruptures, or bleeds. Pain may also occur if the cyst is twisted or causes twisting (torsion) of the fallopian tube. Symptoms of ovarian cysts can include:

• Pelvic pain -- constant, dull aching
• Pain with intercourse or pelvic pain during movement
• Pain during bowel movements
• Pelvic pain shortly after beginning or ending a menstrual period
• Abnormal uterine bleeding (change from normal menstrual pattern)
  • Longer than usual menstrual cycle
  • Shorter than usual menstrual cycle
  • Absent menstruation
  • Irregular menstruation
• Abdominal bloating or swelling

Note: Often no symptoms are noted.

• Pelvic exam -- may reveal an ovarian enlargement or a cyst
• Ultrasound -- usually done first
• CT scan
• MRI
• Doppler flow studies

Blood tests may be ordered:

• Serum HCG (pregnancy test) -- may be done to rule out pregnancy
• Ca-125 -- an ovarian cancer marker that may help to identify cancerous cysts in older women
• Hormone levels (such as LH, FSH, estradiol, and testosterone) -- may be checked to evaluate for associated hormonal conditions