Clinical overview
Uterine leiomyomas (fibroids) are the most common gynaecological tumour: by age 50, ~70% of white women and ~80% of Black women have at least one. In South Africa, the burden is therefore enormous. Most are asymptomatic; symptomatic disease arises from a combination of size, location, and number, producing the clinical phenotypes of heavy menstrual bleeding (heavy-menstrual-bleeding-management), bulk pressure symptoms, pain, infertility, and adverse obstetric outcomes. The registrar's task is to correlate location, size, and histology to symptoms — and to choose between expectant, medical, interventional, and surgical management.
Core knowledge
Pathology
Histology:
- Monoclonal benign smooth muscle tumour.
- Whorled bundles of spindle-shaped smooth muscle cells with abundant eosinophilic cytoplasm.
- Mitotically inactive; nuclear pleomorphism minimal.
- Pseudocapsule of compressed adjacent myometrium (key for surgical enucleation).
- Variable connective tissue stroma.
- Pseudo-vascular system: large peripheral feeding vessels, paucity of internal vasculature — explains susceptibility to ischaemic degeneration.
Genetic and molecular:
- Most have somatic mutations: MED12 (~70%), HMGA2 rearrangements, fumarate hydratase (FH) mutations.
- Steroid hormone-responsive: oestrogen and progesterone drive growth (regress at menopause unless on HRT).
- Familial clustering; hereditary leiomyomatosis and renal cell cancer (HLRCC) — FH mutations.
FIGO classification of fibroid location
This 0–8 system is essential for surgical planning and predicts symptoms:
- Type 0: pedunculated submucosal.
- Type 1: submucosal, <50% intramural.
- Type 2: submucosal, ≥50% intramural.
- Type 3: 100% intramural, contacts endometrium.
- Type 4: intramural.
- Type 5: subserosal, ≥50% intramural.
- Type 6: subserosal, <50% intramural.
- Type 7: pedunculated subserosal.
- Type 8: extrauterine (e.g., cervical, broad ligament, parasitic).
Types 0–2 dominate HMB symptoms; types 5–8 dominate bulk symptoms.
Degenerations
Hyaline, cystic, red and calcific degeneration have distinct appearances that explain symptoms and imaging findings.
- Hyaline degeneration — most common; homogeneous pink replacement of muscle on histology; usually asymptomatic.
- Cystic degeneration — cysts form from coalescent hyaline change; mimics ovarian cyst on imaging.
- Red degeneration — ischaemic infarction in pregnancy. Acute pain, low-grade fever, raised CRP, mildly raised WCC. Self-limiting; analgesia + reassurance. See acute-pelvic-pain-pathophysiology.
- Calcification — late degenerative change; "popcorn" calcifications on imaging.
- Sarcomatous change (leiomyosarcoma) — RARE (<0.5% of clinically diagnosed fibroids); typically presents with rapid growth, postmenopausal growth, MRI features (irregular margins, high T2 signal, restricted diffusion). Important consideration when choosing morcellation (avoid in suspected malignancy) and HRT use after fibroid history.
Clinical correlates by location
Submucosal (types 0–2):
- HMB, IMB, anaemia.
- Subfertility (mechanical obstruction of implantation).
- Recurrent miscarriage.
- Dysmenorrhoea.
Intramural (types 3–4):
- HMB if large or numerous.
- Bulk symptoms if large.
- Subfertility (impact uncertain; large intramural may impair implantation).
Subserosal (types 5–7):
- Pressure symptoms: urinary frequency, hydronephrosis (rare), constipation, low back pain, dyspareunia.
- Pedunculated subserosal (type 7) may tort like an ovary — acute pain.
Cervical (type 8):
- Can obstruct cervical canal.
- Bleeding, discharge.
- Distort surgical anatomy for hysterectomy.
Broad ligament (type 8):
- May displace ureter — risk at surgery.
Assessment
History
- Bleeding pattern (HMB, IMB).
- Bulk symptoms (urinary, bowel, back, abdominal mass awareness).
- Pain (acute or chronic).
- Subfertility, miscarriage history.
- Reproductive intentions.
- Family history.
- Pregnancy possibility.
Examination
- Abdominal: palpable mass (often suprapubic, sometimes umbilical level or higher); mobile or fixed.
- Pelvic: enlarged uterus, often nodular; assess size in centimetres or weeks-of-gestation equivalent.
- Pain: localised to a tender fibroid (degenerating).
Investigations
- FBC (anaemia from HMB).
- Pregnancy test.
- TVS + transabdominal ultrasound — first-line; describes location, size, number, degenerative features.
- Saline-infusion sonography or hysteroscopy — best for cavity involvement (FIGO 0–2).
- MRI — for surgical planning, large complex disease, suspected sarcoma, mapping for myomectomy.
- Endometrial biopsy — if HMB ≥45 or risk factors.
- CT/IV urogram — if urinary tract impingement suspected.
- Hb, ferritin, group-and-save — pre-operative.
- TFTs if coexisting concern.
Management
Expectant
- Asymptomatic fibroids, even large ones, can be observed.
- Annual review.
- Re-evaluate if symptoms develop.
Medical
For HMB-predominant symptoms (smaller fibroids, type 0–2 not distorting cavity):
- LNG-IUS (Mirena) — first-line if cavity reasonably preserved.
- Tranexamic acid.
- NSAIDs.
- Combined hormonal contraception.
For bulk and HMB (larger fibroids):
- GnRH agonists (3–6 months) — reduce fibroid volume ~30–50%, induce amenorrhoea. Used pre-surgical to facilitate vaginal route, reduce bleeding, treat anaemia. Bone loss limits to 6 months without add-back HRT.
- Ulipristal acetate — formerly used; SA availability now restricted due to hepatotoxicity concerns (post-2018 EMA warnings); not first-line currently.
- Relugolix combination (relugolix + estradiol + norethisterone) — newer oral GnRH antagonist combination; available in some markets.
Interventional
Uterine artery embolisation (UAE):
- Suitable for symptomatic fibroids in women not wanting future fertility (relative — increasingly used in fertility-sparing pathway).
- Reduces bleeding 80–90%, bulk symptoms 60–80%.
- ~10–20% require further intervention within 5 years.
- Complications: post-embolisation syndrome (pain, fever, malaise), infection, premature ovarian insufficiency (rare, <5%, mostly in women >45).
Magnetic resonance-guided focused ultrasound surgery (MRgFUS):
- Non-invasive; available in select centres.
- Suitable for selected fibroids.
Surgical
Hysteroscopic myomectomy:
- For FIGO 0–2 fibroids.
- Outpatient or day-case.
- Risks: fluid overload, perforation; complete resection sometimes requires staged procedure.
Laparoscopic / open myomectomy:
- For symptomatic women wanting fertility preservation.
- Risks: bleeding (transfusion sometimes needed), conversion to hysterectomy, recurrence (~30% at 5 years), uterine scar (counsel about delivery in subsequent pregnancy — many centres recommend elective CS).
- Avoid power morcellation if any concern for sarcoma; use contained morcellation if needed.
Hysterectomy:
- Definitive treatment.
- Routes: vaginal (often achievable for moderately enlarged uteri), laparoscopic, robotic, open.
- Surgical considerations: bladder identification, ureteric protection (especially with cervical or broad ligament fibroids), oophorectomy decision separate.
Pregnancy
- Most fibroids do not affect pregnancy outcome.
- Larger and multiple fibroids associated with: miscarriage, preterm labour, malpresentation, dysfunctional labour, placental abruption, postpartum haemorrhage, retained placenta.
- Red degeneration: analgesia, reassurance; rarely surgical.
- Caesarean myomectomy — controversial; usually only for serosal pedunculated fibroids obscuring closure.
Counselling
- Explain expected response: medical 30–70% improvement; surgery near-complete.
- Recurrence — fibroids regrow in ~30% after myomectomy.
- Fertility implications — discuss with reproductive intentions clearly.
- Sarcoma risk — small but real; explain morcellation considerations.
Red flags / pitfalls
- Rapid growth in postmenopausal woman — consider sarcoma; MRI; refer.
- Power morcellation without exclusion of sarcoma — black-box warning in many jurisdictions; use contained morcellation or open surgery.
- Counselling for myomectomy without discussing recurrence.
- Pregnancy after myomectomy — counsel on delivery mode (often elective CS).
- Failing to address anaemia pre-surgery — optimise Hb, iron, sometimes GnRH agonist.
- Misdiagnosing fibroid as ovarian mass (or vice versa) on ultrasound — MRI helps.
- Forgetting bladder/ureter risk in cervical and broad ligament fibroids.
Evidence anchors
- NICE NG88 — Heavy Menstrual Bleeding (fibroid-related HMB section).
- NICE Interventional Procedures Guidance — UAE for fibroids.
- ACOG Practice Bulletin 228 — Management of Symptomatic Uterine Leiomyomas.
- FIGO Classification of Uterine Leiomyomas (Munro MG et al., 2018).
- RCOG Patient Information — Fibroids.
- AAGL Practice Report on the Diagnosis and Management of Submucosal Leiomyomas.
- EMA — Ulipristal Acetate: restricted use due to hepatotoxicity (2018+ position).
- WHO Classification of Female Genital Tumours, 5th edition — leiomyoma vs leiomyosarcoma criteria.
- South African National Department of Health Standard Treatment Guidelines — drug availability and tertiary referral pathways.
- Stewart EA. Uterine fibroids. N Engl J Med 2015 — comprehensive review.