Fibroid uterus (leiomyoma)

Epidemiology
- diagnosed in approximately 40-50% of pre-menopausal women >35 yr
- common indication for major surgery in females
- minimal malignant potential (1:1000)
- typically regress after menopause
Pathogenesis
- estrogen stimulates monoclonal smooth muscle proliferation
- progesterone stimulates production of proteins that inhibit apoptosis
- degenerative changes (occur when tumour outgrows blood supply)
- fibroids can degenerate, become calcified, develop sarcomatous component, or obtain parasitic blood supply

Classification
- intramural: most common, grow within the muscular wall of the uterus
- submucosal: grow within myometrium, can grow into endometrial cavity
- subserosal: grow from the serosa
- fibroids can also grow in the cervix and vagina

Clinical Features
- majority asymptomatic (60%), often discovered as incidental finding on pelvic exam or U/S
- abnormal uterine bleeding (30%): dysmenorrhea, heavy menstrual bleeding
- pressure/bulk symptoms (20-50%)
  - pelvic pressure/heaviness
  - increased abdominal girth
  - urinary frequency and urgency
  - constipation, bloating (rare)
  - acute urinary retention (extremely rare, but surgical emergency!)
- acute pelvic pain
  - fibroid degeneration
  - fibroid torsion (if pedunculated subserosal)
- infertility, recurrent pregnancy loss
- pregnancy complications (potential enlargement and increased pain, obstructed labour, difficult cesarean delivery)

Investigations
- bimanual exam: uterus asymmetrically enlarged, usually mobile
- CBC: anemia
- U/S: to confirm diagnosis and assess location of fibroids
- sonohysterogram: useful for differentiating endometrial polyps from submucosal fibroids or for assessing intracavitary growth
- endometrial biopsy to rule out uterine cancer for abnormal uterine bleeding (especially if age >40 yr) occasionally MRI is used for preoperative planning (e.g. before myomectomy)

Treatment
- only if symptomatic (heavy menstrual bleeding, menometrorrhagia, bulk symptoms), rapidly enlarging or intracavitary
- treat anemia if present
- conservative approach (watch and wait) if:
  - symptoms absent or minimal
  - fibroids <6-8 cm or stable in size
  - not submucosal (submucosal fibroids are more likely to be symptomatic)
  - currently pregnant due to increased risk of bleeding (follow-up U/S if symptoms progress)
- medical approach to treat AUB-L
  - antiprostaglandins (ibuprofen, other NSAIDs)
  - tranexamic acid (Cyklokapron®)
  - CHC, IUS, or Depo-Provera®
  - GnRH agonist: leuprolide (Lupron®)
- interventional radiology approach
  - UAE occludes both uterine arteries, shrinks fibroids by 50% at 6 mo; improves heavy bleeding in 90% of patients within 1-2 mo
  - not an option in women considering childbearing
  - higher risk of surgical re-intervention than with surgical approaches
- surgical approach
  - myomectomy (hysteroscopic, transabdominal, or laparoscopic)
  - hysteroscopic resection of fibroid and endometrial ablation for AUB-Lsm
  - hysterectomy (see Hysterectomy, GY6)
  - note: avoid operating on fibroids during pregnancy (due to vascularity and potential pregnancy loss); expectant management usually best