Each woman has two ovaries, a left and a right one. The ovaries are the main reproductive organs as they contain the eggs, the female reproductive cells. The ovaries also produce the female hormones oestrogen and progesterone.
When tumours grow in the body they can be solid, meaning they contain flesh and are then called lumps or nodules, or they can be cysts which are round structures mainly containing fluid contained by a fine membrane or capsule.
Most ovarian tumours tend to be cystic because of the nature of the ovary. Every month, the ovary prepares an egg to be released at ovulation. The egg matures inside a small ovarian cyst called a follicle. Follicles are “normal” ovarian cysts that can grow up to 3 cm in diameter. They form every month and then break at the time of ovulation.
Ovarian cysts are common and can be thin-walled and only contain fluid (known as simple cysts) or they may be more complex, containing thick fluid or blood, having membranes that divide them into more than one cystic area (septations) or have solid areas in addition to the fluid.
Tumours in general, grow in the body because one cell manages to multiple itself more than it normally should causing a mass of cells where there shouldn’t be one. Because the ovary has several different types of cells, it can grow many different types of tumours. Ovarian cysts can therefore be very different depending on which cell they originate from.
It is also important to know that ovarian cysts can be benign, or malignant (cancerous).
Most cysts that occur before menopause are benign (non-cancerous). Cancer of the ovary before the menopause is rare, but not impossible. Complex cysts in young women, need to be thoroughly investigated.
There are several different types of cysts that can occur. Some of the most common ones are:
Most women will be unaware that they have a cyst as they often cause no symptoms and disappear spontaneously with time. They can also occur in pregnancy. Other cysts may be diagnosed by chance, for example during a routine examination or ultrasound for another reason.
Symptoms from ovarian cysts can be non-specific and confounded with other conditions.
Possible symptoms include:
Sometimes the cyst wall breaks releasing fluid inside the abdomen. This can be very painful and, in many cases, urgent care is needed.
Sometimes the weight of the cyst may cause the ovary to twist. This may compress the artery that brings the blood supply to the ovary. This situation can also cause intense pain and require urgent attention. In rare cases, the ovary starved from the blood supply may experience necrosis requiring its removal.
Large ovarian cysts may be detected by abdominal or internal examination.
The best test to detect cysts however is the ultrasound - either abdominally or internally through the vagina.
If the cyst looks complex, if malignancy is suspected, if it is too big or if it happens in post-menopausal women other tests may be required and these include Magnetic Resonance Imaging (MRI) and blood tests.
The treatment choice depends on the symptoms, the appearance, the size, and the results of any blood tests. It is always a discussion between the woman and her gynaecologist. There are basically three options:
Conservative management (no surgery) and no follow up.
This is the option for small, simple cyst which are completely asymptomatic and where there is no suspicion of malignancy.
Conservative management and repeat imaging, usually an ultrasound after a few months.
This is the option for cysts who do not require immediate surgery when there is no suspicion of malignancy, but follow up is required to check whether the cyst has resolved by itself, has grown, etc. In addition, the way the cyst appearance changes over time may give the doctor more information on what type of cyst it may be.
Surgical removal should be considered for cysts which are large (5cm or more), which cause symptoms of pain or who are thought to possibly be malignant.
The type of surgery usually offered is laparoscopic surgery (keyhole) but if the cyst is solid or very large, a laparotomy (open surgery) may be required.
If the cyst has a benign appearance, the surgery of choice is removal of the cyst with preservation of the ovary.
Up to one in 5 women will have an appointment with a doctor because of an ovarian cyst during their life. About half of them may require surgery.