Leiomyomata

Uterine Leiomyomas, Uterine Myomas, Uterine Fibroids

1. What every clinician should know

Fibroids are the most common neoplasm of the uterus, occurring in 70-80% of all women by age 50. The incidence is related to ethnicity (more common with African ancestry), family history, and fertility status. Very few fibroids are malignant.

2. Diagnosis and differential diagnosis

Diagnostic criteria

Fibroids are usually asymptomatic and may be discovered incidentally on physical examination or imaging studies.

• Examination findings vary and may include a bulky irregular uterus, central abdominopelvic mass, or impression of an adnexal mass.

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There are characteristic findings on ultrasound, CT, and MRI.

• Ultrasound can be used as the primary confirmatory test when there is a suspicion of uterine fibroids.

• MRI can help distinguish whether a potential fibroid arises from the uterus, ovary, or other adjacent structures.

As imaging technologies improve, smaller fibroids can be detected, which raises the likelihood that the fibroids will be falsely blamed for symptoms caused by other pelvic problems.

Fibroids are generally localized to just under the endometrial surface (submucous or submucosal), within the myometrium (intramural), and just under the external uterine serosa (subserosal).

• Submucous myomas may hang from a stalk (pedunculated) and project into the endometrial cavity (intracavitary) or even prolapse through the cervix.

• Subserosal myomas may also hang from a stalk (pedunculated) and project outward into an adnexal location where they can undergo torsion (twisting on their blood supply).

• Rarely fibroids can be found in the retroperitoneum without any attachment to the uterus.

Differential diagnosis

The differential diagnosis of bulky, solid pelvic tumors depends on the organ from which they arise.

• Uterine fibroids have a characteristic appearance on ultrasound examination.

• Degenerating fibroids may be confused with a condition called “adenomyosis” in which endometrial glands and stroma are found in the myometrium and may present as a distinct mass.

• Adenomyosis is usually tender and may change over the course of a menstrual cycle.

• By contrast, uterine fibroids are nontender and slow growing on examination unless they are degenerating.

• Pedunculated submucous myomas can mimic endometrial polyps.

• Pedunculated subserosal myomas can mimic solid ovarian neoplasms.

• A single uterine fibroid that undergoes rapid growth may raise concern about uterine leiomyosarcoma; however, this rare condition affects only 1 in 400-800 fibroid uteri and is no different than the non-rapidly growing fibroid.

• Endometrial biopsy or MRI is a safer method for diagnosing a leiomyosarcoma than hysterectomy, which has a mortality rate of 1-1.5/1000 in women without pelvic malignancies.

3. Management

Because fibroids are common, they often coexist with other causes of pelvic symptoms. Therefore, management often depends on the patient’s main complaint. In addition, It is important to use rigorous diagnostic reasoning for patients who have heavy or irregular uterine bleeding, chronic pelvic pressure/pain, or infertility. The fibroids may be innocent bystanders in these situations. (Please see Figure 1 for a general management plan.)

Figure 1.n

Management when Heavy or Irregular Uterine Bleeding is the main complaint

Fibroids most likely cause abnormal uterine bleeding by distorting the surrounding myometrium, thinning the overlying endometrium, or increasing the endometrial surface area. Typically the bleeding is cyclic but heavy (menorrhagia).

Other causes of abnormal uterine bleeding coexisting with fibroids include anatomic causes (endometrial or cervical polyps, endometrial hyperplasia/cancer), acquired or inherited coagulopathy, uterine infection, or endocrinopathies that lead to chronic anovulation (polycystic ovarian disease, thyroid disorders, obesity/diabetes, and adrenal disorders).

Management of heavy or irregular bleeding due to fibroids starts with medications to regulate menstrual flow, the simplest of which include oral contraceptive pills (OCP) and oral nonsteroidal anti-inflammatory drugs.

• Other routes of delivery for contraceptive steroids include patches (OrthoEvra), vaginal rings (Nuvaring), subdermal implants (Implanon), IUDs (Mirena), and injectable medroxyprogesterone (DepoProvera).

• Injectable GnRH agonists create a menopausal state after an initial stimulatory phase.

• This will stop bleeding from most causes (except neoplasia and infection), much like menopause is the end of regular uterine bleeding.

Surgical choices can be divided into those that preserve fertility (myomectomy) and those that do not.

• Myomectomy: Hysteroscopic

• Preserving fertility by hysteroscopic fibroid resection is an excellent choice for fibroids that extend at least 50% into the endometrial cavity.

• Sometimes larger fibroids will require a staged procedure in which the surgeon safely removes as much fibroid as possible in the first procedure, and then returns a month later to remove the remainder which has been extruded by the myometrium into the endometrial cavity.

• Myomectomy: Abdominal

• Abdominal myomectomies also preserve fertility and can be performed using laparoscopic/robotic or open surgical methods.

• Adjuvant therapy for 2-3 months with a GnRH agonist to shrink the fibroid is an option.

• Adjuvant therapy prior to a myomectomy can affect the ability to find dissection planes due to necrosis and results in a “mushy” fibroid.

Surgical choices that do not preserve fertility include global endometrial ablation for submucous fibroids <2-3 cm in diameter (GEA), uterine artery embolization (UAE), MRI-guided focused ultrasound (not widely available), and hysterectomy.

A reasonable treatment approach for women with fibroids and heavy or irregular uterine bleeding would be:

• Exclude other etiologies of bleeding.

• Begin with medical management.

• If there are contraindications, non-response, or unacceptable side effects to medical management, assess the patient’s desire for fertility, uterine preservation, and definitive symptom control.

• Recommend myomectomy for women wishing to retain their fertility, endometrial ablation or fibroid embolization for women wishing to retain their uterus but not their fertility, and hysterectomy for definitive management.

When counseling younger women (<40) note that distance from menopause is associated with higher rates of treatment failure after myomectomy, EA, and UFE but not hysterectomy.

Management when Pelvic Pressure or Pain is the main complaint

Hysterectomy is the definitive therapy but has the highest risks. Therapy to shrink the fibroid and allow a less morbid route can decrease those risks. Ideally, a vaginal hysterectomy will be performed due to decreased morbidity. Laparoscopic hysterectomy should be the second choice and an abdominal hysterectomy a last resort.

Fibroids most likely cause pelvic pressure due to their increasing bulk (increasing abdominal girth) or by impingement on specific organs (bladder, ureter, rectum) or pelvic nerves.

• Acute abdominal or pelvic pain is a rare complication of fibroids and is found typically in one of three scenarios:

• Torsion of subserosal pedunculated fibroid

• Degeneration of a rapidly growing fibroid (as may occur in pregnancy)

• Attempted uterine explusion of a submucous fibroid

• Other more common etiologies of an acute abdomen should be considered before the fibroid is convicted.

Chronic pelvic pain has many causes and fibroids are rarely involved.

• The etiology is more likely to include endometriosis, adenomyosis, myofascial or neuropathic causes, or chronic conditions of the gastrointestinal or urinary systems.

Fibroids can cause chronic dysmenorrhea by increasing the duration and amount of menstrual blood flow – a condition that should resolve as the bleeding improves with treatment following the recommendations in “Heavy or Irregular Uterine Bleeding.

Management

• For patients wishing to preserve their fertility, reduction in uterine volume by 25-50% may be achieved using GnRH agonist therapy, with return to previous size within 2 years of treatment cessation.

• Removal of large fibroids using laparoscopic or open myomectomy can also bring about substantial reduction in bulk; however. 14-27% of patients require reoperation within 4-10 years.

• For patients wishing to avoid hysterectomy, uterine artery embolization (UAE) can over time produce significant reduction in fibroid size (42% at 3 months), with reoperation rates of 20-40% within 5 years.

A reasonable treatment approach for women with fibroids and pelvic discomfort would be:

• Exclude other etiologies. particularly if pain and not pressure is the most bothersome symptom.

• For patients with painful menses. use the treatment approaches described in “Heavy or Irregular Uterine Bleeding.”

• For patients wishing to preserve fertility. offer myomectomy or GnRH agonist therapy.

• For patients who do not desire future fertility. offer UAE or hysterectomy.

Infertility

Because they are so common, fibroids are frequently encountered when couples are evaluated for infertility. Fibroids that obstruct fallopian tubes are quite rare. Submucous myomas that obscure or distort the endometrium may prompt hysteroscopic removal even when they are not causes of infertility. Randomized trials have not shown an increase in fertility after myomectomy, but several prospective and retrospective studies suggest improved fertility.

4. Complications

The natural progression of fibroids is highly variable, not just from woman to woman, but from fibroid to fibroid, even within the same patient.

Failure to treat fibroids in the truly asymptomatic woman has few, if any, long-term complications.

In symptomatic women, the untreated fibroid may enlarge or shrink and any bleeding may get heavier or resolve.

• As the fibroid grows, the mass effect may cause problems with pelvic pressure/pain, obstructed ureters, varicosities of the legs, rectum and vulva, dyspareunia, constipation, and/or urinary frequency.

• On occasion in pregnancy, cesarean delivery is required due to a cervical or lower uterine fibroid that obstructs vaginal delivery.

The risks of medical management of fibroids are similar to all hormonal therapy, regardless of condition (contraception, endometriosis, dysmenorrhea, or adenomyosis).

• Combined OCP have an increased risk of blood clots, especially in the smoker over the age of 35.

• The use of GnRH agonist is associated with all of the symptoms of menopause including hot flashes, irritability, worsening depression, decreased libido, atrophic vaginitis, and decreased bone density.

• Add-back therapy with norethindrone acetate can decrease hot flashes and bone loss without decreasing effectiveness of the therapy.

UAE has a unique set of complications due to thrombosis, the most common of which include pain and infection from fibroid necrosis and the most serious of which include unintended embolization of other important vessels to the buttocks, bladder or ovary.

The risks of surgical management of fibroids are similar to most surgery. The risk of bleeding, infection, nerve injury and injury to bowel and/or bladder are the most common complications.

• Myomectomy tends to have a higher blood loss than other surgical complications but can be mitigated during surgery with pharmacologic and mechanical decrease in blood flow to the fibroid and surrounding myometrium.

• Hysterectomy for benign fibroids has a mortality of 1-1.5 per 1000 cases.

5. Prognosis and outcome

Table I provides prognosis and outcome information.