Fibroids (also known as uterine leiomyomas or myomas) are the most common benign gynaecological tumour.
- they are monoclonal tumours of the smooth muscle cells of the uterine myometrium
- disorderd myofibroblasts buried in a large amount of extracellular matrix forms a hard, round, whorled tumour
- may be single or multiple with the tumour size varying from few millimetres to 30 cm or more (1,2)
- have minimal malignant potential but may grow to enormous size (1,2)
The incidence of uterine fibroids increases with age.
- in a randomised study carried out in women between the ages of 35-49 years, nearly 70% of white women and more than 80% of black women have had at least one fibroid by the age of 50 years (1)
- 11880 Canadian women between the ages of 20-49 years who were screened for fibroids reported that 12% had been diagnosed with uterine fibroids (including 3.2% reporting current fibroid) (2)
- a review states that an estimated 40% to 89% of premenopausal women have fibroids, which can vary in size from 1 cm to more than 20 cm (3)
- Black women who are affected have a larger number and increased size of fibroids and experience more severe symptoms from fibroids than White women
Cause of fibroids is still unclear, but there is certainly a multi-causal origin
- hormonal factors (ovarian steroid hormones oestrogen, progesterone), genetic factors, growth factors, and the molecular biology of these benign tumours all appear to play a role (4)
- oestrogen is thought to promote fibroid development and growth
- studies have suggested that progesterone may also enhance the growth of fibroids
Majority are asymptomatic and do not require treatment. However, some may cause menorrhagia, infertility and dystocia.
Symptoms attributable to fibroids can generally be classified in three distinct categories:
- abnormal uterine bleeding, pelvic pressure (urinary frequency, constipation) and pain, and reproductive dysfunction (subfertility, miscarriage)
- prolonged or excessively heavy menstruation is the common bleeding pattern of fibroids
- pelvic pressure is caused by pressure on adjacent organs
Most fibroids shrink after menopause since the growth is dependent on the ovarian steroids oestrogen and progesterone
A diagnosis of fibroids may be suspected, based on palpation of an enlarged, irregular uterine contour on pelvic examination
- ultrasonography is typically used to confirm the diagnosis and to exclude the possibility of ovarian neoplasm
- sonohysterography, or diagnostic hysteroscopy is considered to distinguish submucosal fibroids and other intrauterine lesions
- magnetic resonance imaging (MRI) gives better visualisation of individual fibroids
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