Harvey's Garden

Uterine leiomyoma

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aliasesFibroid, Uterine fibromyoma, leiomyoma

4 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)

  • Definition & Subtypes
    • Aggressive mesenchymal uterine tumor.
    • Leiomyosarcoma (LMS) is the most common subtype.
  • Risk Factors
    • Prior pelvic radiation (strongest environmental risk factor).
    • Prolonged Tamoxifen use (> 5 yrs). c
    • Postmenopausal age, African American race.
  • Clinical Presentation
    • Rapidly enlarging uterine mass in a postmenopausal woman.
    • Abnormal uterine bleeding (AUB) / postmenopausal bleeding (PMB).
    • Pelvic pain/pressure, bulk symptoms (urinary frequency, constipation).
  • Diagnosis
    • Initial: Pelvic US (heterogeneous mass, central necrosis, high vascular flow).
    • Endometrial Biopsy: Often negative/non-diagnostic (tumor is intramural, not mucosal).
    • Confirmatory: Surgical histopathology (post-hysterectomy).
    • Staging: Chest CT (metastasis to lungs is #1).
  • Management
    • First-line: TAH-BSO (Total Abdominal Hysterectomy w/ Bilateral Salpingo-Oophorectomy).
    • CRITICAL CONTRAINDICATION: Power morcellation is forbidden (causes peritoneal dissemination).
    • Adjuvant Therapy: Chemotherapy (Doxorubicin-based) or RT for advanced LMS; progesterone/aromatase inhibitors for low-grade Endometrial Stromal Sarcoma (ESS).
  • Differential Diagnosis
    • Uterine Fibroid (Leiomyoma): Premenopausal, slow-growing, benign.
    • Endometrial Carcinoma: Epithelial origin, readily diagnosed on endometrial biopsy.

Treatment

  • Asymptomatic: Observation, as most fibroids shrink after menopause. c
  • 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.

Special patient groups

Uterine leiomyomas during pregnancy

  • Overview & Risk: Estrogen/progesterone-dependent; risk in AA women & advanced maternal age; presents as fundal height > GA.
  • Red Degeneration (Ischemic Necrosis):
    • Trigger: Rapid growth outgrows blood supply (2nd/3rd trimester).
    • Features: Focal pelvic pain, localized fundal tenderness, low-grade fever, leukocytosis.
  • Diagnosis:
    • Pelvic US: Initial & best test (shows hypoechoic pelvic mass; heterogeneous/non-vascular center if degenerating).
  • Management:
    • Red Degeneration: Conservative (hydration + analgesia).
      • Indomethacin: First-line for severe pain if <32 weeks GA (limit <48 hours to prevent ductal closure/oligohydramnios).
    • Surgery: Myomectomy CONTRAINDICATED during pregnancy & during Cesarean section (high risk of severe hemorrhage).
    • Delivery: Vaginal preferred; Cesarean delivery indicated ONLY if fibroid physically obstructs birth canal or causes fetal malpresentation.
  • Complications: Preterm labor, fetal malpresentation (breech), placental abruption, postpartum hemorrhage (uterine atony).

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