Although some ovarian cysts are found in ovarian cancer, most ovarian cysts are considered benign. These cysts are small fluid-filled sacs that form when the follicle (the sac that encloses the egg), fails to rupture and release the egg, which is part of the normal menstrual cycle. When this occurs, the sac and the fluid remain, forming the cyst. Most are harmless, although they occasionally cause problems such as bleeding, rupturing, or pain. The majority of cysts are considering “functional,” meaning that they are a result of normal biological processes, and not associated with any disease.
Types of Ovarian Growths
Follicular cyst: This is a simple, or functional cyst, that forms when ovulation does not occur, or when a mature follicle collapses in on itself. Its rupture, which occurs in the middle of the menstrual cycle, can cause intense pain. Otherwise, the cysts tend to dissolve of their own accord within a few months.
Corpus luteum cyst: After an egg has been released, the follicle becomes what is called a corpus luteum. These usually dissolve, but in some cases they fill with fluid or blood and remain as a cyst. Usually, however, they produce no symptoms.
Hemorrhagic cyst: An ovarian cyst that bleeds, it may cause abdominal pain.
Dermoid cyst: A dermoid cyst is an abnormal ovarian cyst that is a kind of benign tumor capable of growing up to six inches in diameter. It is formed not of fluid, but of fat, and sometimes bone, hair, and cartilage.
Cystadenoma: This kind of ovarian cyst is composed of ovarian tissue. It is a benign tumor that can grow up to twelve inches in diameter.
Endometriomas or endometroid cysts: These cysts are formed as part of endometriosis, in which the tissue that lines the uterine wall grows in other locations, such as the ovaries.
Polycystic-appearing ovary: An ovary that appears twice its normal size on an ultrasound is often enlarged due to a number of small cysts growing on its outside walls.
Possible Risks for Developing Ovarian Cysts
- History of previous cysts
- Irregular menstrual cycles
- Increased upper body fat distribution
- Early menstruation (11 years or younger)
- Hyperthyroidism or hormonal imbalances
- Tamoxifen treatment for breast cancer
Oral contraceptives can reduce the risk of ovarian cysts, since they prevent the ovaries from producing eggs during ovulation.