Uterine fibroids are benign tumors which grow from the muscle layers of the uterus. They are the most common benign neoplasm in females. Often asymptomatic, they cause symptoms in about 25% of white and 50% of black women. Uterine fibroids often do not require treatment, but when they are problematic, they may be treated surgically or with medication — possible interventions include a hysterectomy, hormonal therapy, a myomectomy, or uterine artery embolization. Estrogen receptors on uterine fibroids cause fibroids to be larger in reproductive years and shrink dramatically in size after a woman passes through menopause. Uterine fibroids are more common in overweight women and women of coloured descent.
Fibroids are named according to where they are found. There are four types: Intramural fibroids are found in the wall of the womb and are the most common type of fibroids. Subserosal fibroids are found growing outside the wall of the womb and can become very large. They can also grow on stalks (called pedunculated fibroids). Submucosal fibroids are found in the muscle beneath the inner lining of the womb wall. Cervical fibroids are found in the wall of the cervix (neck of the womb). In very rare cases, malignant (cancerous) growths on the smooth muscles inside the womb can develop, called leiomyosarcoma of the womb.
The symptoms depend on the size, location, number, and the pathological findings. Fibroids, particularly when small, may be entirely asymptomatic. The U.S. Department of Health & Human Services states that “Fibroids are almost always benign (not cancerous). Rarely (less than one in 1,000) a cancerous fibroid will occur. This is called leiomyosarcoma. Doctors think that these cancers do not arise from an already-existing fibroid. Having fibroids does not increase the risk of developing a cancerous fibroid. Having fibroids also does not increase a woman’s chances of getting other forms of cancer in the uterus.” Generally, symptoms relate to the location of the lesion and its size. Important symptoms include abnormal gynecologic hemorrhage, heavy or painful periods, abdominal discomfort or bloating, back ache, urinary frequency or retention, and in some cases, infertility. There may also be pain during intercourse, depending on the location of the fibroid. During pregnancy they may be the cause of miscarriage, bleeding, premature labor, or interference with the position of the fetus.