Uterine leiomyomas

Uterine leiomyomas are common, benign (noncancerous) tumors located in the uterus (womb). They are composed of smooth muscle that is gradually replaced by fibrous connective tissue (hence their common name, fibroids). Leiomyomas are distinct, firm and round. They often occur in groups. They are classified according to their location.

• Intramural leiomyomas are located within the muscular wall of the uterus.
• Subserous leiomyomas are those located on the outside surface of the uterus.
• Submucosal leiomyomas are located on the inside of the uterus lining.

Leiomyomas can be located in the cervix, or found within the broad ligaments (intraligamentous). A leiomyoma may even be detached from the uterus, obtaining its blood supply from other abdominal organs (parasitic). A submucosa leiomyoma may be attached by a stem (pedunculated) making it subject to torsion (twisting) or infection.

Since their growth is promoted by estrogen, leiomyomas generally grow during pregnancy and cease to grow with menopause. If estrogen replacement therapy is used after menopause, leiomyomas may still grow. Oral contraceptives may also cause them to grow. The cause of leiomyomas is unknown. These tumors are found in 30 to 50% of women over 30 years of age.

History: In non-pregnant women, leiomyomas are frequently asymptomatic (without symptoms). If symptoms are present, they may include frequent urination, constipation, painful menstrual periods (dysmenorrhea), bleeding between menstrual periods, or excessive menstrual bleeding (menorrhagia). Deterioration (degeneration) can occur, causing intense pain. Severe pain can also occur if a pedunculated leiomyoma becomes twisted on its stem (torsion) or has its blood supply obstructed. Infertility may be caused by a leiomyoma that has significantly distorted the uterine cavity. In pregnancy, a leiomyoma may cause miscarriage (spontaneous abortion) by the second month.

Physical exam: Leiomyomas are easily discovered by bimanual examination of the uterus (examination done by pressing uterus between hand inserted into the vagina and other hand on top of abdomen), or palpation of lower abdomen (exam done by pressing down on abdomen with hand).

Tests: A pelvic ultrasound can assist in the diagnosis and exclude pregnancy as the cause of uterine enlargement. MRI and hysteroscopy (examination of the inside of the uterine cavity done with a special viewing instrument) can depict the number, size, and location of the tumors. A hematocrit blood test may reveal a low hemoglobin level (anemia) due to excessive menstrual bleeding.

Small, asymptomatic leiomyomas are usually not treated, but should be observed at six-month intervals. Leiomyomas do not usually require surgery unless they cause significant pressure on adjacent organs (ureters, bladder, or bowels), severe bleeding leading to anemia, or they are growing rapidly. Cervical leiomyomas or those that protrude through the cervix need to be removed.

Myomectomy (removal of the leiomyoma) is the treatment of choice during the childbearing years because future pregnancies are possible. However, leiomyomas may recur. Under certain circumstances, hysterectomy may be performed and cures the problem.