Ovarian Cysts

Ovarian cysts are very common and can cause women a great deal of stress. Sometimes they are found after an ultrasound is done because of pain or other symptoms, but sometimes they are found by accident when women are having an ultrasound done for a completely different reason and they are not having any symptoms at all.

In pre-menopausal women, very often an ovarian cyst will be functional (related to the normal functioning of the ovary) and benign. Each month with ovulation, a sac of fluid fills up around the egg that will be ovulated. This can be seen as a “simple cyst” or “physiologic cyst” and will normally resolve on its own after ovulation occurs. Sometimes after ovulation occurs, some bleeding will happen around the sac that contained the egg and it can fill up, creating a “hemorrhagic cyst”. These also normally resolve on their own but can take a bit longer. There are various other conditions in which benign cysts might be seen on the ovaries, such as PCOS, endometriosis, or during pregnancy. Sometimes an infection will cause a collection on or near the ovary. Usually imaging can give us a good idea as to whether an ovarian cyst is benign and likely to go away on its own, or whether it has more suspicious features that warrant following it or doing other investigations or even surgery to remove it.

In post-menopausal women, the risk of a cyst being ovarian cancer is higher than for younger women, but ovarian cysts can still be benign. There are features on ultrasound that are more suspicious for cancer, such as solid components, thick septations or nodules within the cyst, or ascites (fluid in the abdomen/pelvis). When these are present, a blood test called CA125 is often done. This is a tumour marker that can be elevated with ovarian cancer. It can also be elevated with other non-cancerous conditions and therefore it is not a good screening test, but when an abnormality has been seen on ultrasound it can help determine whether it is likely to be benign or malignant and help guide treatment decisions.