---

Uterine Leiomyoma (Fibroids) - MBBS Gynecology

---

1. Definition and Basic Science

• They are the most common benign tumors of the female genital tract
• The most frequent indication for hysterectomy (~240,000/year in the US)
• They are not premalignant - malignant transformation to leiomyosarcoma is very rare

---

2. Incidence / Epidemiology

• Incidence rises with age: 4.3 per 1,000 woman-years at age 25-29, rising to 22.5 per 1,000 at age 40-44
• Never seen before puberty; regress after menopause

---

3. Pathogenesis / Etiology

Hormonal Role (KEY)

• Fibroids are estrogen and progesterone dependent
• Serum levels of both hormones are the same in women with and without fibroids, BUT:
  • Fibroids have increased aromatase → higher local de novo estradiol production
  • Fibroids have increased progesterone receptors A and B compared to normal myometrium
  • Highest mitotic counts are found at the peak of progesterone production
• GnRH agonists shrink fibroids; concurrent progestins block this shrinkage
• The antiprogestin RU-486 (mifepristone) blocks fibroid growth

Growth Factors

• TGF-β, bFGF → smooth muscle proliferation + ECM synthesis
• EGF, PDGF → increase DNA synthesis
• VEGF, bFGF → promote angiogenesis

---

4. Risk Factors

---

5. Classification by Location (FIGO System)

• Submucosal (Types 0-2): bulge into uterine cavity → most likely to cause bleeding and infertility
• Intramural (Type 4): within muscle wall → most common type
• Subserosal (Types 5-7): project outward → cause pressure symptoms

---

6. Fibroid Variants (Gross Pathology)

Exam pearl: Red degeneration (carneous degeneration) occurs specifically during pregnancy. It presents with acute localized pain + fever + tenderness over the fibroid. Managed conservatively with analgesics.

---

7. Clinical Features

Symptoms (remember: ~50% are asymptomatic)

• Heavy/prolonged menstrual bleeding (menorrhagia)
• Submucosal fibroids are the most likely culprit
• The number and size of fibroids do NOT predict bleeding severity - location matters most
• Mechanism: distorted endometrium, impaired contractility, vascular changes

• Dull, dragging lower abdominal pain
• Dysmenorrhea
• Degeneration causes acute pain
• Torsion of pedunculated subserosal fibroid → acute abdomen requiring surgery

• Urinary frequency/urgency (anterior fibroid compressing bladder - most common)
• Hydronephrosis (lateral fibroid compressing ureter)
• Constipation, tenesmus (posterior fibroid)

• Submucous fibroids are most likely to impair fertility
• Other types rarely cause infertility alone

---

8. Effects in Pregnancy

• Fibroid degeneration (red degeneration) - in ~5-9%, causes severe pain
• Increased cesarean section rate (49% vs 21% without fibroids)
• Increased preterm delivery risk (19.2% vs 12.7%)
• Placenta previa (3.5% vs 1.8%)
• Postpartum hemorrhage (8.3% vs 2.9%)
• Rarely: placental abruption (especially retroplacental fibroids)
• Fetal injury from mechanical compression is uncommon

---

9. Diagnosis

Clinical Examination

• Bimanual pelvic examination: enlarged, irregularly shaped, firm, nontender uterus
• Correlates well with uterine size at pathology even in obese women

Investigations (in order of preference)

Routine sonographic examination is not necessary when clinical diagnosis is almost certain on bimanual examination.

---

10. Natural History

• Most fibroids grow slowly - median growth rate ~9% over 12 months
• Multiple fibroids in the same woman can have highly variable growth rates
• Growth rates decline with age in white women but not African American women
• 7% of fibroids regress spontaneously
• All fibroids shrink after menopause

Rapid Growth

• "Rapid uterine growth" in premenopausal women RARELY = sarcoma
• Only 1 sarcoma found among 371 women operated on for rapid growth (0.26%)
• Uterine sarcoma is a concern mainly in postmenopausal women with pain and bleeding

---

11. Management

A. Conservative (Observation)

• Asymptomatic women: regular follow-up
• No routine serial ultrasound needed for stable, asymptomatic fibroids

B. Medical Treatment

GnRH agonist preoperatively: Shrinks fibroid, corrects anemia, reduces intraoperative blood loss before myomectomy/hysterectomy

C. Surgical Treatment

• Heavy bleeding causing anemia not responding to medical treatment
• Significant pressure symptoms compromising quality of life
• Infertility with submucosal fibroid
• Acute pain (degeneration, torsion)
• Ureteral obstruction
• Desire for definitive treatment

• Myomectomy is a safe alternative to hysterectomy, even for large fibroids
• 80% symptom relief reported after myomectomy
• Risk of uterine rupture in subsequent pregnancy: 0.47% (similar to VBAC)
• Fibroids can recur after myomectomy

D. Interventional Radiology

• Embolizes uterine arteries → infarction of fibroids
• Reduces mean uterine volume by 35%
• Urinary frequency and urgency: greatly/moderately improved in 68%
• Effects on ovarian reserve, fertility, and future pregnancy are unclear - counsel patients appropriately

---

12. Preoperative Anemia Management

• IV iron is superior to oral iron (Hb increase 3.0 vs 0.8 g/dL)
• Epoetin 250 IU/kg/week x 3 weeks reduces transfusion rates
• GnRH agonist + oral iron for 12 weeks: 74% achieve Hb >12g (vs 46% with iron alone)

---

13. PALM-COEIN Classification (AUB)

---

14. Key Exam Points to Remember

1. Most common benign tumor of the female genital tract
2. Monoclonal origin from a single smooth muscle cell
3. Most common symptom = menorrhagia (especially submucosal)
4. Pressure symptoms: urinary frequency is most common (anterior fibroid)
5. Submucosal fibroid = most likely to cause bleeding and infertility
6. Red degeneration = occurs in pregnancy; managed conservatively
7. Rapid growth in premenopausal women is NOT a sign of malignancy
8. GnRH agonists: shrink fibroids by 30-35% but only temporarily
9. UAE is effective but avoid in women wanting future pregnancy
10. Fibroid in PALM-COEIN = AUB-L
11. Never seen before puberty; regress after menopause (estrogen/progesterone dependent)
12. Malignant transformation is very rare (<1 in 1,000)

---