Are ovarian cysts common?

There are different types of ovarian cysts, some more common than others. Ovarian cysts are fluid-filled spaces that can develop within or on the ovary. The good news is most ovarian cysts present with no symptoms, are harmless and resolve themselves.

Who is at risk of developing ovarian cysts?

Ovarian cysts can occur in women of all ages, but are particularly common in premenopausal women. Women may not be aware they have a cyst until symptoms develop. Most ovarian cysts in young women are functional cysts that come and go and which develop during the menstrual cycle.

Functional vs non-functional cysts

Functional cysts develop during a women’s normal menstrual cycle as a result of a hormonal imbalance and are called either a follicular or corpus luteum cyst. Functional cysts are common. Non-functional (neoplastic) ovarian cysts are less common and grow without the influence of hormones. The exact causes of non-functional ovarian cysts are unknown. 

Functional ovarian cysts

FAQ Words Written on Paper

Types of functional ovarian cysts:

  • Follicular cyst: Each month, the ovary grows tiny sacs (follicles) that hold the eggs. Follicles release an egg when a woman ovulates. A follicular cyst develops when the ovary fails to release an egg or when a follicle in the ovary continues to grow after an egg has been released.
  • Corpus luteum cyst: Once a follicle releases its egg, it then begins producing sex hormones estrogen and progesterone for conception. This follicle is called the corpus luteum. A corpus luteum can grow into a cyst when, in some cases, fluid accumulates inside the follicle.

These functional ovarian cysts usually resolve without treatment within a few months.

Non-functional ovarian cysts                              

Types of non-functional (neoplastic) ovarian cysts include:

  • Dermoid cysts: Sac-like benign growths on the ovaries that can contain hair, fat, teeth, bone and other tissue. Growing teeth in the ovaries sounds very strange but dermoid cysts develop from totipotential germ cells, sometimes referred to as 'master cells' because of their ability to mature into any type of tissue.  These cells can become over stimulated in women during their reproductive years (mainly 30s).
  • Cystadenomas: Benign growths that can develop on the outer surface of the ovaries. They can be filled with a transparent, watery fluid or can be filled with mucus.
  • Endometriomas: Tissues that normally grow inside the uterus can develop outside the uterus and attach to the ovaries. Endometriomas occur due to a condition called endometriosis. Endometriomas develop mostly in women below the age of 50 years and may be associated with painful periods.
  • Polycystic ovarian syndrome (PCOS) stands for ovaries with innumerable tiny ovarian cysts. These cysts do not normally need to be removed, but women with PCOS may need treatment for other PCOS problems.  


Symptoms can differ in women. Depending on its size, some cysts cause pelvic pain and in functional cysts the pain is short term. Large cysts can cause persisting pain and discomfort, pelvic pressure, bloating, feeling of fullness or urinary frequency. Irregular menstrual periods are not usually related to an ovarian cyst.


Ovarian cysts are typically diagnosed during a pelvic examination or a pelvic ultrasound.

Risks of ovarian cysts

Ovarian cysts, such as dermoids in particular, can grow large and may cause ovarian torsion. This is rare but occurs when a large cyst causes an ovary to twist around its own blood supply or move from its original position.  Ovarian torsion can also decrease or cut off the blood flow to the ovaries, resulting in severe acute pain. Ruptured cysts can cause intense pain and internal bleeding. Ovarian torsion and ruptured cysts require immediate treatment.

Is the cyst cancerous?

Overall, the vast majority of new growths on or near the ovary are benign and not related to ovarian cancer.

Unfortunately, there is no 100% reliable test (or combination of tests) to check if an ovarian cyst is harmless or ovarian cancer. However, a few tests can be done to assess the probability of an ovarian cyst being malignant (cancer) or benign.

  • Ultrasound: The ultrasound will show if the ovarian cyst is purely cystic (a simple cyst) or if it contains some solid elements. Ovarian lesions that are solid (not fluid filled) cannot be called cysts, and require further investigation. If an ovarian mass contains solid parts, the risk of this mass being cancerous is higher.
  • Patient age: Ovarian cancer mainly affects women after the age of 50 years.
  • Tumour marker blood tests: There are blood tests which will help to estimate the risk of cancer including CA125, CA19.9, HE4. While tumour markers are not specific for cancer, elevated blood tumour markers are associated with a higher risk of malignancy.

In summary, a women less than 50 years of age, with a simple ovarian cyst (no solid elements) and a low CA125 blood test has a very low risk that her ovarian cyst could be malignant.


If ovarian cysts are causing severe symptoms (for example pain), or if they grow or change in appearance then surgery to remove the cyst may be recommended. In young women, the surgical procedure may involve removing only the cyst if it is small and appears non-cancerous. In postmenopausal women, I recommend removing the entire ovary (not just the cyst). Having one ovary removed will not cause women to go through menopause and does not cause infertility. Removing both ovaries in young women will cause infertility.

The majority of these surgical procedures are completed laparoscopically requiring small (6 mm) incisions near the navel (keyhole) with a hospital stay of one night. If the cyst is large or appears suspicious for cancer, it may be necessary to have an open incision through the abdomen.

For suspicious cysts and ovarian masses, I recommend a frozen section examination. This means that I invite a pathologist into the operating theatre who will snap freeze the tissue and examine whether there is cancer while the patient is still asleep. 

If you wish to discuss assessment and treatment of ovarian cysts with Dr Obermair, please enquire about an appointment via the contact us page. 

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