What are ovarian cysts?

A cyst is a fluid-filled sac, and can be located anywhere in the body. On the ovary, different types of cysts can form. The most common type of ovarian cyst is called a functional cyst, which often forms during the normal menstrual cycle. Each month, a woman's ovaries grow tiny cysts that hold the eggs. When an egg is mature, the sac breaks open to release the egg (ovulation), so it can travel through the fallopian tube for fertilization. Then the sac dissolves. In one type of functional cyst, called a follicular cyst, the sac doesn't break open to release the egg and may continue to grow. This type of cyst usually disappears within one to three months. A corpus luteum cyst, another type of functional cyst, forms if the sac doesn’t dissolve. Instead, the sac seals off after the egg is released. Fluid then builds up inside of it. This type of cyst usually goes away on its own after a few weeks. However, it can grow to almost four inches and may bleed or twist the ovary and cause pain. Although not common, a twisted ovary (torsion of the ovary) is very painful and is a medical emergency.  Clomid or Serophene, which are drugs used to induce ovulation, can raise the risk of getting this type of cyst. These cysts are almost never associated with cancer.

There are also other types of cysts:

  • Endometriomas. These cysts develop in women who have endometriosis, when tissue from the lining of the uterus grows outside of the uterus. The tissue may attach to the ovary and form a growth. These cysts can be painful during sexual intercourse and during menstruation. 
  • Cystadenomas. These cysts develop from cells on the outer surface of the ovary. They are often filled with a watery fluid or thick, sticky gel. They can become large and cause pain.
  • Dermoid cysts. Some cells in the ovary make hair, teeth, and other growing tissues that become part of a forming ovarian cyst. These cysts can become large and cause pain.
  • Polycystic ovaries.  The eggs do not fully mature within the follicles, or sacs, and some of these follicles may remain as very small cysts in the ovary.  The cycle repeats, additional follicles start to grow inside the ovary, the eggs do not fully mature and cysts form. For more information, See Polycystic Ovary Syndrome.



Ovarian Cysts Questions

Information is provided by:  The National Women's Health Information Center which is Sponsored by the Office on Women's Health in the U.S. Department of Health and Human Services