Ovarian Cysts

What are ovarian cysts?

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.

What are the types of ovarian cysts?

Functional cysts develop as part of a normal menstrual cycle. These include:

1. 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 ovarian cyst.

2. 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 ovarian 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:

1. 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.

2. Dermoid cystssia
   

   Dermoid ovarian 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.
   

3. Cystadenomas
   

   These arise from the outer surface of the ovary and may contain fluid or mucoid contents.
   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.

What are the symptoms of ovarian cysts?

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 (dyspareunia).

Other symptoms include:

• menstrual irregularities
• bloatedness
• lower abdominal discomfort
  
• loss of appetite or weight
• 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.

What are the risk factors for ovarian cysts?

Risk factors include:

• Older age
• Previous history of breast cancer
• Family history of ovarian cancer
• Obesity
• Taking hormone replacement therapy

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 possibility.

How are ovarian cysts diagnosed?

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.

How are ovarian cysts treated?

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 cyst.

Surgery will be recommended if the ovarian cyst is symptomatic or has abnormal features.

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 faster recovery.

Laparotomy (open surgery) may be recommended if you have had previous surgery, if the ovarian cyst is large or if it has suspicious features.

Cystectomy involves the 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 surgical staging.

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 nodes.