There are two types of functional cysts (also known as simple cysts): Follicle cysts and corpus luteum cysts. Functional cysts rarely cause pain and often disappear on their own without any intervention.
- Follicle Cysts: During the menstrual cycle, an egg grows in a sac called a follicle, which is in the ovaries. Usually this sac will break open and release an egg (Ovulation!). Sometimes the follicle won’t break open and the fluid inside the follicle can form a cyst on the ovary. This is part of normal female physiology and rarely causes any issues. That being said, occasionally ovulation can cause a small amount of bleeding into an ovary (a hemorrhagic cyst), and this can be painful. The good news, though, is that even hemorrhagic ovarian cysts often resolve on their own without intervention, kind of like a bruise that can be sore at first but then gets better. Even though this type of bleeding can occur in both follicular cysts and corpus luteum cysts, it is still pretty uncommon.
- Corpus luteum cysts: During ovulation an egg is released from a follicle. If pregnancy occurs, the follicle will seal off and a mass of cells on the inside will help produce progesterone during early pregnancy. This progesterone is important in maintaining a pregnancy and this cyst will continue to produce this hormone until the placenta takes over. This type of cyst is usually easily visualized on ultrasound in early pregnancy.
- Dermoid cysts: These are also known as teratomas and can contain hair, skin and teeth because they form from embryonic cells. While this sounds scary, these cysts are usually benign and very slow growing. If they are large, they can cause pain and you may at risk for ovarian torsion (torsion is where the ovary twists on itself which decreases the blood flow to the ovary and can cause severe pain). In this situation, your doctor may encourage you to have it removed. However, if it is small, it is reasonable to watch it unless it is causing problems.
- Cystadenomas: This is a benign tumor that arises from the surface of the ovary and can be filled with fluid or mucous. Often these can be very large which can cause pain and increase your risk of ovarian torsion. Based on the appearance, size and whether it is causing symptoms, your provider may encourage you to have it removed.
- Endometriomas: These are blood filled cysts that form on the ovaries because of a condition called endometriosis. Treatment of endometriosis and endometriomas is complex and you will likely need to have an extensive discussion with your provider based on symptoms and appearance on imaging.
- Polycystic Ovaries: Polycystic ovarian syndrome is a condition where multiple small simple ovarian cysts form because of a hormone imbalance that prevents ovulation. This can cause menstrual irregularities and infertility. Treatment would be geared towards symptoms being experienced by PCOS.
- Cancer: While this is not common, some ovarian cysts can be malignant as well