Harvey's Garden

Uterine leiomyoma

3 min read

Epidemiology

Etiology

Predisposing factors

  • Nulliparity
  • Early menarche (< 10 years of age)
  • Age: 25–45 years
    • Fibroids are largely found in women of reproductive age.
    • Influenced by hormones (i.e., estrogen, growth hormone, and progesterone)
    • During menopause, hormone levels begin to decrease and leiomyomas begin to shrink.
  • Increased incidence in African American individuals

Pathophysiology

Clinical features

  • Symptoms depend on the number, size, and location of leiomyomas. Often asymptomatic (up to 80% of cases).
  • Abnormal menstruation (possibly associated with anemia): hypermenorrhea, heavy menstrual bleeding, metrorrhagia, dysmenorrhea
    • Submucosal leiomyomas are most frequently associated with significantly prolonged or heavy menstrual bleeding. The mechanism may be related to the increased total surface area as a result of the bulging uterine wall, impaired uterine wall contractility, or micro/macrovascular abnormalities.
  • Features of mass effect
    • Enlarged, firm and irregular uterus during bimanual pelvic examination
      • Size can range from normal to full-term gestation
      • Differ from Adenomyosis, which shows globular, uniformly enlarged uterus that is soft but tender on palpation
    • Back or pelvic pain/discomfort
    • Urinary tract or bowel symptoms (e.g., urinary frequency/retention/incontinence, constipation, features of hydronephrosis)
  • Reproductive abnormalities
    • Infertility (difficulty conceiving and increased risk of pregnancy loss)
      • Related to an obstructed uterine cavity and/or impaired contractility of the uterus.
    • Dyspareunia

Diagnostics

Warning

Uterine leiomyomas are extremely common (affecting 70% of women) and are often found incidentally on ultrasound; do not attribute abnormal uterine bleeding to leiomyomas until other etiologies have been ruled out!

Pathology

  • Macroscopic
    • Grayish-white surface
    • Homogeneous; tissue bundles on cross-section partly in a whorled pattern
    • Some leiomyomas may involve regressive changes: scar formation, calcification, and cysts
  • Microscopic: Smooth muscle tissue in a whorled pattern with well-demarcated borders, consisting of monoclonal cells interspersed with connective tissue

Differential diagnostics

Uterine leiomyosarcoma (uterine sarcoma)

Rare malignant tumor arising from the smooth muscle cells of the myometrium

  • Risk factors
    • Menopause
    • Tamoxifen use
      • Because it stimulate the ER on uterine myometrium
  • Uterine findings
    • Rapidly enlarging
  • Pathology
    • Single lesions with areas of coagulative necrosis and/or hemorrhage
    • Cords of polygonal cells with eosinophilic cytoplasm, abundant mitoses, and cellular atypia are common.

Treatment

  • Asymptomatic: Observation, as most fibroids shrink after menopause.
  • Medical (symptom control):
    • Hormonal contraceptives (e.g., OCPs) or progestin-releasing IUDs can manage heavy bleeding but do not shrink fibroids.
    • GnRH agonists (e.g., leuprolide) induce a temporary menopause-like state, shrinking fibroids. Used short-term pre-operatively due to significant side effects.
  • Surgical/Procedural:
    • Myomectomy: Surgical removal of fibroids while preserving the uterus. This is the choice for patients who desire future fertility.
    • Hysterectomy: Definitive treatment, removing the uterus and thus curing the fibroids.
    • Uterine Artery Embolization (UAE): A minimally invasive procedure where embolic agents block blood flow to the fibroids, causing them to shrink.

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