Uterine fibroids

Fibroids are non-cancerous tumours that grow within the wall of the uterus and are made up of smooth muscle and fibrous connective tissues. The size of fibroids varies and can be as small as a blueberry, mid-range in size like a kiwi or can be as big as a watermelon. Larger fibroids can even fill the entire abdomen and extend to the rib cage.

It is estimated that about 20-80% of women develop fibroids. African-American women are 3 times more likely to have fibroids compared to White women. The cause of fibroids is not known although a genetic component has been postulated. Fibroids may be single or, more commonly, multiple. Many women with fibroids do not have symptoms. Women who do have symptoms could present with heavy or prolonged menstrual bleeding, pelvic pain and pressure, frequent urination, difficulty getting pregnant and pain during intercourse.

Growth of fibroids is dependent on the hormones oestrogen and progesterone. Hence, fibroids thrive in women of reproductive age, are often enlarged during pregnancy or with oral contraceptive use, and shrink after menopause.

Classification of fibroids rely on their location in the uterus (Image 1). Fibroids can be classified as submucosal (projecting into the endometrial cavity), intramural (within the substance of the uterus) or subserosal (in the substance beneath the serous membrane of the uterus). Intramural fibroids are the commonest type of fibroids but are often asymptomatic. The least common fibroids are the submucosal type but these are the ones that cause the most symptoms and may be associated with abnormal vaginal bleeding and infertility. In rare instances, submucosal fibroids may be pedunculated with a stalk, and protrude into the uterine cavity. Subserosal fibroids are usually asymptomatic.

Diagnosis is usually via ultrasound (US) pelvis. Magnetic resonance (MR) imaging however is the most accurate imaging technique for detection and localisation of fibroids (Image 2). MR imaging also has a role in treatment of fibroids whereby it can assist in surgical planning and monitoring response to medical therapy.
Approximately 80% of patients with uterine fibroids do not exhibit symptoms and do not require treatment. For patients who have symptoms, medical or surgical treatment may be indicated and this is decided by the gynaecologist, occasionally with assistance of an interventional radiologist, depending on the nature of the fibroid. Treatment depends on several factors such as severity of the symptoms, size and location of the fibroid, age and desire of getting pregnant in future.


1. Sue W and Sarah SB, Radiological appearances of uterine fibroids. Indian J Radiol Imaging. 2009 Aug; 19(3): 222-231. Last accessed: 8 January 2022. 

2. Deshmukh SP, Gonsalves C, Guglielmo FF and Mitchell D. Role of MR Imaging of Uterine Leiomyomas before and after Embolisation. Radiographics 2012, Vol 32(6). https://doi.org/10.1148/rg.326125517. Last accessed: 8 January 2022. 

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