Ovarian Cysts

What are ovarian cysts?

A cyst is like a balloon filled with fluid. The majority of cysts in the ovary are physiological (natural or functional). As ova (eggs) start to mature they develop in follicular cysts. These generally reach up to 2.5 cms diameter. Occasionally they can reach 4 or 5 cms diameter. The vast majority of small cysts will disappear without treatment. Sometimes these cysts continue to release hormones delaying the onset of the next period. the Question of pregnancy then arises. If there is associated pain, the possibility of an ectopic pregnancy (Q12.23) needs to be considered. Modern pregnancy tests are very sensitive and a negative result excludes this diagnosis.

Endometriosis may result in chocolate filled cysts of the ovaries (Q 23.18). In polycystic ovary syndrome (Q7. 2) the cysts are small varying from 2-8 mm. They are not cysts that need to be removed and they do not seem to cause pain.

True ovarian cysts may continue to increase in size. Every sort of tissue within an organ has the potential to form a tumour, which can be benign or malignant. As the ovaries contain most tissue types including eggs that have the potential to produce every tissue, there is a greater variety of tumours of the ovaries than for any other organ. With increasing age of the patient there is a greater chance of an ovarian cyst proving to be malignant. When there is concern that an ovarian cyst could be malignant a blood test for a tumour marker (Ca-125) may provide guidance (Q32.25).

How do ovarian cysts cause pelvic pain?

Moderate sized cysts may undergo torsion (twisting) and this cuts off their blood supply causing acute pain. Bleeding into an ovarian cyst, even a physiological cyst, can be the cause of pain. A cyst may rupture (burst) releasing blood or fluid that irritates the peritoneum (peritonism Q 23.6). Some of the clinical manifestations of peritonism, notably pain and tenderness may be similar to those found in peritonitis (inflammation of the peritoneum). Peritonitis, which is a dangerous condition, has the additional evidence of infection including an elevated temperature and a high white blood cell count. An endometrioma (a collection of old blood associated with endometriosis - Q 23.18) can be associated with pain, although at times even large collections may be pain free.

How are ovarian cysts diagnosed?

Ovarian cysts can cause discomfort and occasionally pain in the pelvis or bladder pressure symptoms including increased frequency of micturition (bladder emptying - Q 29.9). An ovarian cyst may be recognised during a routine pelvic examination or if it is particularly large it can be felt on examination of the abdomen. The majority of patients referred to me with an ovarian cyst have had the diagnosis made from an ultrasound examination that was requested to investigate pelvic pain. Most of these cysts will prove to be physiological and will resolve without treatment.

How are ovarian cysts treated?

If the cyst is physiological, it will disappear spontaneously within a few weeks or months. If the cyst seems to be simple (no structures within the cyst), it can be drained through a fine needle under ultrasound guidance or at laparoscopy. Aspiration of a cyst, however, has been shown to be no better than observation alone^1996-01. There may be an occasional indication for aspiration in those who would be at risk from surgery^1993-01. Larger cysts may need surgical removal. Many can be treated laparoscopically.

For young women, the aim of treatment is to be as conservative as possible. When there is acute severe pelvic pain associated with an ovarian cyst in a young woman emergency surgery may be required. The objective is to remove the cyst and conserve the remainder of the ovary. When a woman in her forties or beyond presents with pain associated with an ovarian cyst serious consideration would need to be given to removing both ovaries and the uterus (Q32.33A). Ultrasound examination is required to provide further details of the swelling. Areas of solid tissue associated with the cyst(s) reduce the chance of the cyst being innocent. An exact diagnosis can only be provided by full detailed microscopic assessment (histopathology) of the cyst.     

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