Ovarian cysts are very common: approximately 10% of women have an operation during their life, for investigation of an ovarian cyst / mass. The underlying causes of ovarian cysts can range from the utterly banal and benign (eg. an ovulation cyst), to the outright malignant (ovarian cancer). Investigations to differentiate between the two (and all other types of ovarian cysts) can cause significant anxiety. Please read on, to get a sense as to how and why your gynaecologist might investigate and treat your ovarian cyst(s)!

What are ovarian cysts?

An ovarian cyst is a fluid-containing structure (with or without solid parts), within or on the outside of the ovary, generally more than 3cm in diameter. In pre-menopausal women, almost all ovarian cysts are benign (non-cancerous).

What symptoms can ovarian cysts cause?

Ovarian cysts can cause pretty vague symptoms, such can be challenging to diagnose based on symptoms alone.

Vague abdominal / pelvic discomfort

Ovarian cysts may cause pelvic discomfort or pain, often on the left / right side (depending on whether the cyst is on the left / right ovary). This pain may be worse during your period (esp. for endometriotic ovarian cysts, which are called endometriomas).

If you have severe, sudden-onset, one-sided pelvic pain that lasts for over two hours,  and a known ovarian cyst: please attend the emergency department of a local hospital with a gynaecology department. (This is especially true if you have associated nausea and/or vomiting). This may be due to your ovary twisting on itself (an ‘ovarian torsion’), which may require urgent keyhole surgery (to de-twist the ovary).

Abdominal distension / bloating

Ovarian cysts (especially when they are large) can cause persistent abdominal distension, or bloating. This kind of distension will be there all the time: it doesn’t fluctuate up and down based on what you’ve eaten, where you are in your menstrual cycle, whether your bowels are full or not.

Urinary symptoms

If you have a large ovarian cyst, it may press onto your bladder, and decrease your bladder’s capacity. This means that your bladder can’t hold as much urine, and may mean that you feel the need to empty your bladder more often.

No symptoms at all

Quite often, you may have an ultrasound (or other imaging, such as a CT or MRI) for another reason: eg. to investigate other symptoms, such as lower back pain. This imaging may happen to show that you have an ovarian cyst, which isn’t causing you any specific symptoms. This is called an ‘incidental finding’: when we happy to find something on imaging that we weren’t necessarily looking for, or expecting.

What are the risk factors for ovarian cancer?

In pre-menopausal women, almost all ovarian cysts are benign (non-cancerous). If you are pre-menopausal, and have a symptomatic ovarian cyst, the baseline risk of it being cancerous is approximately 1 in 1,000 (ie. 0.1%).

Family history

If there are several members of your family who have had: breast, colorectal, uterine and / or ovarian cancer, you may be at higher risk of ovarian cancer. In particular, if these are first-degree relatives, and if they were diagnosed earlier in life (eg. prior to 50yo). If this is the case, your doctor may refer you to the local familial cancer clinic, for discussions around possible genetic testing (eg. for the BRCA or Lynch syndrome genes).

Increasing age

Broadly speaking, ovarian cancer is more likely the older you are, up until 70yo. The risk of ovarian cancer peaks in your mid-60s.

What investigations will my doctor order?

An internal (transvaginal) ultrasound is the key investigation, in terms of ovarian cysts. Your doctor may also order some blood tests (called ‘tumour markers’), especially if your ovarian cyst is described on ultrasound as being ‘complex’.

Transvaginal (internal) ultrasound

Transvaginal ultrasound is the single most effective way of evaluating an ovarian mass or cyst. While uncomfortable, it is much more accurate than a transabdominal (external) ultrasound.

Experienced sonologists (ultrasound experts) can often guess what type of ovarian cyst you have, based on what it looks like on ultrasound.

If you do not feel comfortable having an internal ultrasound, your doctor may suggest another form of imaging instead, such as a CT.

Tumour marker blood tests

If your ovarian cyst is described on ultrasound as being ‘complex’ (rather than ‘simple’), your doctor may order some blood tests. These are called ‘tumour markers’, and the main one is called CA125. CA125 is not a perfect screening test for ovarian cancer, in that it can be normal in the presence of ovarian cancer, and abnormally high due to common and benign (non-cancerous) conditions (such as fibroids and endometriosis).

Seeing a gynaecologist can help to put together all the pieces of the puzzle: your symptoms, your family history, your ultrasound report, and your blood test results. They can then guide you as to how your ovarian cyst(s) can be managed.

How are ovarian cysts managed?

The management of ovarian cysts is quite nuanced, and depends on:

• Whether or not the ovarian cyst is causing you any symptoms
• The likely type of ovarian cyst, as suggested by an expert clinician with a specialist women’s ultrasound
• The size of the cyst
• Your CA125 blood test result (if this was completed)
• Whether or not you would like definite confirmation that it is not cancerous (as this can only be confirmed with surgical removal of the cyst, and a pathology doctor looking at the ovarian cyst under a microscope)

In the sections below, I’ve outlined the possible management, based on the type of ovarian cyst that is suspected on your specialist ultrasound.

What are the different types of ovarian cysts?

The most common types of benign (non-cancerous) ovarian cysts are outlined below. An expert sonologist (ultrasound clinician) can often guess what type of ovarian cyst you have, based on what it looks like on ultrasound. This ‘pattern recognition’ is more likely if you have a specialist women’s ultrasound through a company with the appropriate expertise (eg. Siles Health, Western Imaging for Women).

Simple / follicular / functional cyst

When a woman ovulates, an egg is released from a sac of fluid (called the ‘corpus luteum’) on the ovary. Sometimes, fluid accumulates in that sac after ovulation: this fluid accumulation is called a simple, follicular or functional ovarian cyst. On ultrasound, these cysts essentially look like a round bag of fluid.

Any ovarian cysts that are described as ‘simple’ on ultrasound are almost certainly benign (non-cancerous), as they don’t have any suspicious features that there is anything nasty going on.

If you have a simple cyst that is < 5cm in size found on ultrasound, and you don’t have any symptoms (eg. pain on that side): this cyst will likely resolve over the coming three menstrual cycles. There’s no need for any management, nor any follow-up ultrasounds.

If your simple cyst is > 5cm and / or causing you symptoms, your doctor may suggest a repeat ultrasound in at least three months’ time (ideally in the first half of your menstrual cycle). If your simple cyst is stable or getting smaller, and your symptoms are improving, nothing more needs to be done. If your simple cyst is getting bigger, or your symptoms are worse, it’s worth seeing a gynaecologist.

Haemorrhagic cyst

A haemorrhagic cyst occurs sometimes following ovulation: when an egg is released from an ovary, a little blood vessel (a ‘capillary’) may burst, and a blood clot collect inside the pocket where the egg was released from. More often than not, this blood clot is slowly absorbed over the following few months.

If a haemorrhagic cyst is suspected on ultrasound, best practice is to have a repeat ultrasound at least 3 months later. If the cyst is stable, or is getting smaller, you can be pretty reassured that there is nothing else going on. No additional follow-up is needed.

If, on the other hand, the cyst is the same size or getting bigger, it’s worth seeing a gynaecologist for review. Sometimes haemorrhagic cysts may be mistaken for endometriotic cysts (see below).

Endometriotic cyst / endometrioma

As outlined in previous blog posts, endometriotic ovarian cysts (called ‘endometriomas’) are a form of moderate to severe endometriosis. (An endometriotic cyst ≥ 3cm in size automatically means that you have at least stage 3, or moderate, endometriosis.)

If your ultrasound shows an endometrioma that is < 5cm in size, and you don’t have any significant period pain or infertility, your doctor may suggest a repeat ultrasound in 3 months’ time. If at that stage, your endometrioma is getting bigger, you have developed symptoms or issues conceiving, or any suspicious features have developed: you need to see a gynaecologist with expertise in the surgical excision of endometriosis, such as Maven Centre’s Dr Alison Bryant-Smith or Dr Sneha Parghi.

They will be able to talk you through having, and perform, keyhole surgery to remove your endometriotic cyst (plus any additional endometriosis that you may have).

If you have both a large endometrioma, plus are struggling to conceive, a gynaecologist with fertility expertise (such as Maven Centre’s Dr Melissa Cameron) may help to guide your management.

Dermoid (aka. mature teratoma)

Dermoid cysts (the formal name for which is ‘mature teratomas’) are fascinating, in that they often contain hair, sebum, and even teeth. (I once had a patient with a large dermoid cyst that contained a fully-formed left jaw bone, complete with 8 teeth!) Because of their somewhat unusual contents, dermoid cysts are relatively easy to diagnose on ultrasound or CT.

Approximately 1 – 5% of all teratomas are actually found to be cancerous (when examined under a microscope); these are known as ‘immature teratomas’. Because of this, gynaecologists often recommend that dermoid cysts are removed surgically, as that is the only way that we can confirm that yours is completely benign.

Fibroma

Fibromas are the most common type of solid (rather than fluid-filled) ovarian mass. They look very similar to fibroids, both on ultrasound and at surgery: fibroids are very common, non-cancerous overgrowths of the uterine muscle. Both fibromas and fibroids are hard, white, globular growths. It can be so hard to tell a fibroma and a fibroid apart on ultrasound, that fibromas are often misdiagnosed as fibroids, especially on a basic (non-specialist) ultrasound.

If an ovarian fibroma is suspected on ultrasound, you need to see a gynaecologist, for discussions around having it removed with keyhole surgery.

Non-ovarian cysts

Approximately 10% of ‘ovarian cysts’ seen on ultrasound are eventually found not to be ovarian cysts at all, when keyhole surgery is undertaken! The following entities are often mistaken for ovarian cysts on imaging:

• Hydrosalpinx: a swollen Fallopian tube, which is full of fluid
• Tubo-ovarian abscess: an abscess (collection of pus) in the Fallopian tube, which is an extreme form of pelvic inflammatory disease (PID)
• Para-fimbrial cyst: a cyst (bag of fluid) next to the fimbria (or fronds) of the Fallopian tube

What is a complex ovarian cyst?

There are several features which, if found on ultrasound, make an ovarian cyst ‘complex’. These include:

• Having lots of locules (or little pockets) within the cyst. These may be called ‘complete septations’
• Solid areas (or ‘nodules’)
• So-called ‘papillary projections’, which are nipple- or finger-like growths that are seen projecting into the inside an ovarian cyst
• Very strong blood flow

In addition, if ascites (excess fluid in your abdominal / pelvic cavity) is seen, a high quality ultrasound should comment upon this.

The features above increase the likelihood that your ovarian cyst is actually pre-cancerous or cancerous. If so, your clinician should order a series of blood tests, called ovarian cancer tumour markers, as outlined below.

Ovarian cancer tumour markers

Tumour markers if you’re < 40yo

If you’re < 40yo, your doctor should order the following ovarian cancer tumour markers:

• CA125 HE4 and ROMA score
• Germ cell tumour markers (AFP, hCG, LDH)

These aren’t perfect markers of ovarian cancer, in that they can be abnormally high in completely benign (non-cancerous) conditions. For example, CA125 can be somewhat raised due to endometriosis, adenomyosis, or fibroids, which are much more common than ovarian cancer.

The HE4 tumour marker is not covered by Medicare, and costs approximately $45 out-of-pocket. But it is much more sensitive to ovarian cancer in pre-menopausal patients: it is less likely to be abnormally high in non-cancerous conditions (such as endometriosis). So that might be $45 well-spent, to provide some peace-of-mind… H3: Tumour markers if you’re > 40yo

Tumour markers if you’re > 40yo

For women > 40yo, germ cell tumours are much less likely. Hence, the suggested ovarian cancer tumour markers include only:

• CA125
• HE4 and ROMA score

Please see discussion of these blood tests in the section above: this is also relevant for women > 40yo.

What happens then?

If you are pre-menopausal, and have been found on a high quality specialist women’s ultrasound to have a complex ovarian cyst, your Maven Centre gynaecologist may recommend that you see a gynaeoncologist (a gynaecologist who has completed an additional three years of training, in the management of gynaecological cancers). This is for an expert second opinion, regarding the likelihood of your ovarian cyst being benign / malignant. The gynaeoncologist may be best placed to take over your care from that point onwards, or may recommend that you stay under the care of Maven Centre’s benign gynaecologists.

Why might my gynaecologist recommend surgical removal of my ovarian cyst(s)?

There are various reasons why your gynaecologist may recommend keyhole surgery to remove your ovarian cyst(s); this operation is called ‘laparoscopic ovarian cystectomy’. These reasons include:

• You have significant symptoms, that can be attributed to your ovarian cyst(s)
• Your cyst has been found on repeat ultrasound to be getting larger over time
• To definitively exclude pre-cancerous or cancerous cells within your ovarian cyst: surgical excision is the only way to find out exactly what type of ovarian cyst you have, as it enables a pathology doctor to look at it under a microscope
• To decrease the chance of future complications, such as ovarian torsion. This is when the ovary and Fallopian tube twist on their stalk, thereby cutting off their own blood supply. This can mean that the ovary dies, which reduces your fertility in future. Surgically removing an ovarian cyst is thought to decrease the chances of ovarian torsion happening in future.
• If you are thought to have possible endometriosis, which requires surgical excision in any case. Please see this blog post about the surgical management of endometriosis, for a more detailed discussion about this.

Topic area frequently asked questions (FAQs)

I’ve been found to have any endometrioma on specialist ultrasound. What are the odds that this is actually cancerous?

Overall, what is thought to be a benign (non-cancerous) endometriotic cyst on specialist ultrasound has a < 1% chance of actually being cancerous (when it is cut out, and looked at under a microscope). If your endometrioma is > 9cm in diameter and/or you are > 45yo, this risk is slightly higher. In these cases, your gynaecologist is likely to recommend surgical removal (rather than a ‘wait a see’ approach), to confirm that your suspected endometrioma is, in fact, benign.

My ovarian cyst has been described as ‘simple’ on ultrasound. Do I still need to have ovarian cancer (‘tumour marker’) blood tests?

If you’ve had a high quality, specialist women’s ultrasound that has described your ovarian cyst as ‘simple’, it’s extraordinarily unlikely that your ovarian cyst is actually cancerous. Hence, your doctor probably won’t recommend any ovarian cancer tumour marker blood tests.

In this context, if you do have these blood tests done, it’s possible that a co-existing benign condition (eg. endometriosis, adenomyosis, or fibroids) may make some of these blood tests (eg. CA125) abnormally high, which may cause unnecessarily anxiety and concern.

These discussions can be quite nuanced: when in doubt, please ask your gynaecologist any such questions that you may have.

If I have an operation to remove an ovarian cyst, will I also lose my ovary?

In the vast majority of cases, skilled gynaecological surgeons are able to remove your ovarian cyst surgically, while maintaining your ovary: this operation is called an ‘ovarian cystectomy’.

Very rarely, if your ovarian cyst is very large (eg. > 10cm), we may not be able to find any functional ovarian tissue near it. So we may not be able to remove your ovarian cyst without also removing the ovary on that side: an operation called an ‘oophorectomy’. We will do all we can to preserve your ovary, but may warn you before your operation that there is a risk that we may not be able to save the ovary on the affected side.

My gynaecologist said that my cyst might be too small to remove surgically. Why is this?

Sometimes, small ovarian cysts (ie. < 3cm in size) can be quite challenging to find surgically. Your ovarian cyst may be on the inside of your ovary; at surgery, we can only easily see the outside surface of your ovary. To find small internal ovarian cysts, we need to cut through the overlying normal ovarian tissue: akin to searching through a haystack for a needle. Doing so can impact upon your ovarian function, which may impair your fertility in future. Such situations require a nuanced discussion with your gynaecologist, about the pros and cons of us ‘going hunting’ for a small ovarian cyst surgically.

Conclusion

Ovarian cysts are very common, and their investigations (such as an ultrasound +/- tumour marker blood tests) can provoke significant anxiety. A specialist women’s ultrasound can often help to clarify the exact type of ovarian cyst that is present. The management of ovarian cysts often needs a detailed, nuanced discussion with an expert gynaecologist, such as those at Maven Centre.