What’s the Difference between an Ovarian Cyst vs a Follicular Cyst

Written by Dr. Nirvana

January 22, 2021

Many women may have follicular cysts but don’t have PCOS. Do you know how to differentiate between the two? In this artilce, I’d like to discuss how you can.

One of the main difference is in their size:

  • a follicle is 10mm or 2cm or smaller
  • a dominant follicle is 20-30mm or smaller
  • an ovarian cyst is larger than 30mm (3cm) in size

We don’t usually consider surgery unless a cyst is larger than 50-60mm (5-6cm) although that may depend on what the cyst looks like & what symptoms it causes. Ovarian cysts are so common that nearly every woman will have 1 at some stage in her life. Many women will have no problems related to a cyst.

There are 3 main groups of ovarian cysts:

  1. Functional (physiological) cysts. They form when the monthly ovarian cycle doesn’t follow its usual pattern. These form when the dominant follicle & corpus luteum do not behave as they normally would during a particular menstrual cycle. They are called either follicular or corpus luteum cysts.
  2. Follicular cysts form when the follicle does not release an egg but instead continues to swell up with fluid. In the same way, a corpus luteum cyst forms when the corpus luteum does not shrink away but continues to grow in size. Functional cysts are common & usually go away by themselves, but this can take 2 – 3 months. After the cyst goes away, the ovary usually goes back to working normally. From time to time, another functional cyst may occur. Not surprisingly, your period may not come at the right time in a cycle affected by a functional ovarian cyst. Often the period comes later than expected but it can come earlier. However, once the cyst has resolved, the menstrual cycles return to normal. Just remember, they’re common & mostly resolve by themselves without treatment.
  3. Benign (non-cancerous) ovarian cysts are also common.
    1. Dermoid cysts (aka teratomas) are benign ovarian tumors which contain many different body tissues – fat, hair, skin & even teeth. They occur mostly in young women & are even found in children. In women with a dermoid cyst, 10% will have 1 in both ovaries. Dermoid cysts are ‘growths’, but many grow so slowly (1 – 2 mm per year) that surgery is often not recommended unless they reach about 5cm.
    2. Cystadenomas are benign tumors containing clear, water-like fluid or mucus. On ultrasound, they often look just like functional cysts – the difference is that functional cysts usually go away over a few months while cystadenomas keep getting bigger over time. Once a cystadenoma is about 5 – 6 cm in size & has been there for several months (so it’s not likely to be a functional cyst), you & your gynecologist may decide to have it removed, as it may twist the ovary or burst in the future (but not common).

What about Polycystic Ovaries?

PCO means ‘many cysts on the ovary’ but the ‘cysts’ that are seen in this condition are not true cysts – instead PCO actually means having lots of small follicles (2 – 9mm). This is often normal for young women and is not usually Polycystic Ovary Syndrome (PCOS), particularly if they have regular periods and no abnormal facial or body hair or have insulin resistance. However, if a woman only has a period every few months and/or she also has a problem with facial/body hair, acne, and blood sugar imbalances, she may have PCOS. In PCOS, the hormones don’t follow the normal menstrual cycle & has many small ovarian follicles. These are not true ovarian cysts and generally don’t require surgery.

What should I do if think I have an ovarian cyst?

If your symptoms are mild then you should see your GP, who will ask you about your symptoms and examine you. It may be possible for your doctor to feel a cyst by checking your abdomen or by vaginal examination. Your GP will most likely request:

  1. A pap smear if it’s due.
  2. A pregnancy test if there is a possibility you may be pregnant. A pregnancy in the wrong place (the tube, rather than the uterus) can give symptoms just like an ovarian cyst. This type of pregnancy is called an ectopic pregnancy. [see our Fact Sheet on Ectopic Pregnancy]
  3. A pelvic ultrasound– either through the tummy wall or else through the vagina (called a transvaginal US). A scan through the vagina is close to the ovaries and gives much clearer pictures than a scan through the tummy. A vaginal scan is not uncomfortable, especially since it doesn’t need a full bladder. Ultrasound is excellent at seeing a cyst on the ovary and working out what kind of cyst it is.
  4. Rarely, ovarian cysts can cause particular blood tests to become abnormal. Your doctor will decide if you need these tests.

Management of an Ovarian Cyst

If you have an ovarian cyst, managing it will depend on what type of cyst it is, how big it is, and what problems you are experiencing.  Functional cysts can be watched for a few months as they will usually go away on their own. You & your gynecologist may decide to have the cyst removed if it doesn’t go away on its own after 3 months, if it’s causing significant pain/pressure symptoms, if it’s quite big (more than 6cm) or if it’s a type of cyst that doesn’t go away by itself (like a dermoid).

What about taking the oral contraceptive pill?

Taking the pill won’t treat a cyst if it’s already there & it may go away by itself. It’s more like a band-aid to a long-term issue and the pill will block androgen production too. This isn’t a good thing because women need healthy testosterone production for bone health, libido, stamina and mood enhancement. Long-term affects to imbalanced hormone production in the future is also a risk, as well as blood clot formation. In the end remember that the pill only masks the root cause of the hormonal imbalances that are occurring in PCOS. Addressing your adrenal health, blood sugar imbalances and making sure your liver detox pathways are working optimally, is a good place to start. Your body is so intelligent. When one area is out of balance, another area is also. So begin by searching for the reason the cyst formation happened in the first place, will help your body be free to work and maintain its health naturally.  I’m here to help you discover where it all started.

difference between ovarian cyst and follicular cyst

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