Uterine leiomyomas, the most common benign tumors in women, are also known as myomas,fibromyomas, or fibroids. They're tumors composed of smooth muscle that usually occur in the uterine corpus, although they may appear on the cervix or on the round or broad ligament. Uterine leiomyomas occur in 20% to 25% of women of reproductive age and may affect three times as many Blacks as Whites, although the true incidence in either population is unknown.
Leiomyomas are classified according to location. They may be located within the uterine wall (intramural) or protrude into the endometrial cavity (submucous) or from the serosal surface of the uterus (subserous). Of varying size, they're usually firm and surrounded by a pseudo capsule composed of compressed but otherwise normal uterine myometrium. The uterine cavity may become larger, increasing the endometrial surface area. This can cause increased uterine bleeding. Tumors become malignant (leiomyosarcoma) in less than 0.1 % ofpatients, which should serve to comfort women concerned with the possibility of a uterine malignancy in association with a fibroid.
The cause of uterine leiomyomas is unknown, but some factors implicated as regulators of leiomyoma growth include:
- several growth factors, including epidermal growth factor
- steroid hormones, including estrogen and progesterone (because leiomyomas typically arise after menarche and regress after menopause, which implicates estrogen as a promoter of leiomyoma growth), and growth factors.
- genetic predisposition.
Signs and symptoms of Uterine Leiomyomas
Approximately one-third of women with uterine leiomyomas experience pain, which may manifest itself as dysmenorrhea, dyspareunia (painful intercourse), or chronic lower abdominal or back pain. Although most uterine leiomyomas are asymptomatic, when present, signs and symptoms include:
- abnormal bleeding, typically hypermenorrhea with disrupted submucosal vessels (most common symptom)
- pain only associated with torsion of a pedunculated (stemmed) subserous tumor or leiomyomas undergoing degeneration (when the fibroid outgrows its blood supply and shrinks down in size, which can be artificially induced through myolysis, a laparoscopic procedure to shrink fibroids, or uterine artery embolization)
- pelvic pressure and impingement on adjacent viscera (indications for treatment, depending on severity) resulting in mild hydronephrosis (not believed to be an indication for treatment because renal failure rarely, if ever, results)
- urinary frequency, urinary incontinence, or urinary retention due to pelvic pressure on the urinary bladder. constipation due to pressure on the GI tract.
Various complications and disorders have been attributed to uterine leiomyomas, including recurrent spontaneous abortion, preterm labor, malposition of the fetus, anemia secondary to excessive bleeding, bladder compression, infection (if tumor protrudes out of the vaginal opening), secondary infertility (rare), and bowel obstruction.
Current research suggests that there's a strong genetic component, specifically a mutation in the fumarate hydratase gene, related to the development of uterine leiomyomas. Although more research is necessary, identifying the possible gene is promising for future treatment of uterine leiomyomas
Diagnosis of leiomyoma may be based on:
- clinical findings (enlarged uterus) and patient history suggesting uterine leiomyomas
- blood studies showing anemia from abnormal bleeding (may support the diagnosis)
- bimanual examination showing enlarged, firm, non tender, and irregularly contoured uterus (also seen with adenomyosis and
other pelvic abnormalities)
- ultrasound for accurate assessment of the dimension, number, and location of tumors
- magnetic resonance imaging (especially sensitive to fibroid imaging).
Other diagnostic procedures include:
- endometrial biopsy (to rule out endometrial cancer in patients over age 35 with abnormal uterine bleeding)
Treatment of Uterine Leiomyomas
Treatment depends on the severity of symptoms, size and location of the tumors, and the patient's age, parity, pregnancy status, desire to have children, and general health. If not severe, treatment may be managed conservatively until the woman reaches menopause, when fibroids most commonly regress.
Treatment options include non surgical and surgical procedures. Pharmacologic treatment generally isn't effective in the long term for fibroids. Although usually prescribed by gynecologists, progestational agents are ineffective as primary treatment for fibroids.
In addition to observation, nonsurgical methods include:
- gonadotropin-releasing hormone (GnRH) agonists to rapidly suppress pituitary gonadotropin release, which leads to profound hypoestrogenemia, a 50% reduction in uterine volume (with peak effects occurring in the 12th week of therapy), and consequent benefit of reduction in tumor size before surgery, decreased blood loss during surgery, and increased preoperative hematocrit (best used preoperatively or for up to 6 months in a perimenopausal woman because tumors increase in size after cessation of therapy)
- nonsteroidal anti-inflammatory drugs for dysmenorrhea or pelvic discomfort.
Surgical procedures include:
- abdominal, laparoscopic, or hysteroscopic myomectomy (removal of tumors in the uterine muscle) for patients of any age who want to preserve their uterus
- myolysis (a laparoscopic procedure to treat fibroids without hysterectomy or major surgery, performed on an outpatient basis) to coagulate the fibroids and preserve the uterus and childbearing potential
- uterine artery embolization (radiologic procedure) to block uterine arteries using small pieces of polyvinyl chloride (promising alternative to surgery for many women, but unsupported by long-term studies on success rate, adverse effects, or effects on childbearing and recent anecdotal data suggest decreased time to menopause after embolization)
- hysterectomy (definitive treatment for symptomatic women who have completed childbearing; must involve detailed patient teaching about all available options)
- blood transfusions (with severe anemia due to excessive bleeding).
Special considerations and Prevention
- Tell the patient to report abnormal bleeding or pelvic pain immediately.
- Reassure the patient that she won't experience premature menopause if her ovaries are left intact.
- In a patient with severe anemia due to excessive bleeding, administer iron
- Supplements and blood transfusions, as ordered.
- Encourage the patient to verbalize her feelings and concerns related to the disease process and its effects on her lifestyle.
- Prior to undergoing surgery, help patients to understand the effects of hysterectomy or oophorectomy, if indicated, on menstruation, menopause, sexual activity, and hormonal balance. Patients should also understand that pregnancy is still possible if multiple myomectomy is necessary, though cesarean delivery may be necessary. Extensive scar tissue may rupture during the contractions of vaginal delivery. (Violation of the endometrial cavity is the classic indication for cesarean delivery in such patients, but it's unclear why a cell layer 1 to 2 cells thick should be protective against uterine dehiscence in subsequent pregnancy.)