There are several types of ovarian cyst, each with its own cause, according to Medical News Today. Ovarian follicles that swell with fluid cause follicular cysts. When the corpus luteum fills with blood, it forms a luteal ovarian cyst. Dermod cysts are tumors created from totipotential germ cells, which are the cells that create eggs in the ovaries. The outer cells of the ovary create cystadenomas, which usually attach to the ovaries via a stalk.
Endometriosis and polycystic ovarian syndrome both increase the risk of women developing ovarian cysts, explains Medical News Today. Endometriosis is a condition that causes the cells that create the uterine lining to grow outside of the uterus. Polycystic ovarian syndrome, which is a hormonal problem caused by the ovaries, also increases the chance of women developing benign ovarian cysts.
Doctors divide ovarian cysts into two categories, notes Medical News Today. Functional ovarian cysts, such as follicular and luteal cysts, are harmless and usually disappear within a few weeks to a few months without treatment. They are a common part of many women's menstrual cycles.
Pathological ovarian cysts, such as dermod cysts or cystadenomas, form in the ovaries and are either benign or cancerous, according to Medical News Today. Because totipotential germ cells have the potential to create any type of bodily tissue, dermod cysts sometimes contain bone, teeth or hair. They are rarely cancerous but require surgical treatment. Watery liquid or a thick mucous fills cystadenomas. A surgeon removes these cysts, although benign cysts are common.