Ovarian cysts are fluid-filled sacs that form within the ovary. They vary in size and content, and may be benign or malignant. Most cysts are asymptomatic and non-cancerous, and resolve spontaneously without any treatment.
Functional cysts develop as part of a normal menstrual cycle. These include:
a) Follicular cysts
New follicles develop during the start of each menstrual cycle. Each contains fluid that protects a developing egg, which is released at the time of ovulation. If the follicle fails to release the egg, it may continue to grow and form a follicular cyst.
b) Corpus luteum cysts
If ovulation takes place, the follicle develops into a corpus luteum. This produces progesterone, which modifies the womb lining to prepare it for pregnancy. The corpus luteum typically dissolves if pregnancy does not take place, but may occasionally bleed or swell with fluid to form a corpus luteal cyst.
The majority of functional cysts resolve spontaneously over two to three menstrual cycles. However, some may continue to grow or even twist or rupture and cause acute symptoms.
Polycystic ovaries are ovaries containing multiple small follicles. This may be seen in conjunction with irregular menses, subfertility and symptoms of hormonal imbalance like oily skin, acne and increased hair growth.
Benign ovarian cysts include:
a) Endometriotic cysts
Endometriosis occurs when cells from the womb lining develop outside the womb. Deposits of these cells on the ovary can result in the formation of endometriotic cysts. These cysts contain thick, dark brown material, and are frequently adherent to surrounding structures such as the uterus, opposite ovary or intestines, which may make surgery more challenging.
b) Dermoid cysts
Dermoid cysts develop from germ cells, which are cells that are able to develop into any type of body tissue. They may therefore contain various types of tissue including teeth, hair and fat, and are more commonly seen in younger women.
These arise from the outer surface of
the ovary and may contain fluid or
A proportion of ovarian cysts are
cancerous (malignant). Pregnancy,
breastfeeding, usage of the oral
contraceptive pill, previous sterilisation
and removal of the uterus are
associated with a lower chance of
developing ovarian cancer.
The majority of ovarian cysts are
asymptomatic. Larger ovarian cysts
may twist or rupture, resulting in
acute abdominal pain, nausea and
vomiting. Patients with endometriotic
cysts may present with painful menses
(dysmenorrhoea) and intercourse
Other symptoms include menstrual
irregularities, bloatedness, lower
abdominal discomfort, loss of appetite
or weight, and passing urine more
frequently or change in bowel habit
(constipation or diarrhoea) due to
compression from the cyst.
As ovarian cancer tends to develop
insidiously with vague symptoms,
the above symptoms should not be
ignored, especially if they are new or
experienced on a frequent basis.
Risk factors include:
However, as many people who develop
cancer have no risk factors, it is
imperative that all women with ovarian
cysts are properly evaluated for this
Ultrasound is the preferred method for characterising ovarian cysts. Features such as solid areas, multiple internal compartments, irregular margins and high velocity blood flow increase the index of suspicion for ovarian cancer.
A blood test for CA125 may be taken if
there is concern about malignancy. This
blood protein is frequently raised in
ovarian cancer, but must be interpreted
in conjunction with symptoms and
ultrasound findings as it can also be
raised in non-cancerous conditions
such as endometriosis and fibroids.
Management depends on your
symptoms, characteristics of the cyst
and results of blood tests.
Small asymptomatic ovarian cysts
that have no suspicious features
on ultrasound may be managed
expectantly. This usually involves a
follow-up ultrasound scan in about
three to four months to monitor for any
change in size or appearance of the
Surgery will be recommended if the
cyst is symptomatic or has abnormal
Laparoscopy (keyhole surgery) is
the approach of choice if the risk of
malignancy is low, as it is associated
with less post-operative pain and a
Laparotomy (open surgery) may be
recommended if you have had previous
surgery, if the cyst is large or if it has
Cystectomy involves removal of the
cyst with preservation of normal
ovarian tissue. This is usually done for
pre-menopausal women in order to
conserve ovarian tissue for reproductive
and hormonal function.
Oophorectomy is the surgical
procedure to remove the entire ovary.
Post-menopausal women will usually
be offered removal of both ovaries as
this has the advantage of reducing the
risk of developing ovarian cancer or
cysts in the future.
If the risk of ovarian cancer is high, your
doctor will discuss frozen section and
Frozen section involves sending the
excised ovarian tissue for microscopic
examination while you are still under
general anaesthesia. If this test reveals
malignant cells and you have given
prior consent, your surgeon may then
proceed to perform a full staging
surgery as part of the treatment for
ovarian cancer. This involves removing
the uterus, both fallopian tubes and
ovaries, the omentum (a layer of fatty
tissue that covers the abdominal
contents like an apron) as well as lymph
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