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Hydatidiform Mole

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Hydatidiform Mole, Hydatid Mole, Molar Pregnancy

  • See Also
  1. Trophoblastic Neoplasia
  1. North America and Europe: 1:1000 to 1:1500 pregnancies
  2. Asia and Latin America: 1:400 to 1:200 pregnancies
  3. Philippines: 1:250
  • Risk Factors
  1. Prior Molar Pregnancy
  2. Extremes of reproductive age
    1. Age under 20 years
    2. Age over 45 years
  3. Twin Gestation
  4. High Parity
  5. Malnutrition
  • Pathophysiology
  1. Form of Trophoblastic Neoplasia
    1. Benign proliferation of chorionic villi
    2. Fetus absent
  2. Choriocarcinoma (risk: 10-20%) predisposing factors
    1. Complete hydatiform mole
    2. Abnormally proliferative trophoblast
    3. Pitocin or Hysterectomy for mole evacuation
    4. Oral Contraceptive use after mole evacuation
  • Types
  1. Complete Mole
    1. Total hydatidiform change
    2. Marked proliferation of trophoblastic cells
    3. No evidence of fetal vessels
    4. Karyotype: 46XX (all paternally derived)
      1. Derived from haploid 23X sperm
      2. Sperm duplicates Chromosomes without cell division
    5. Higher risk for malignant change
  2. Partial Mole
    1. Associated with non-viable fetus or vessels only
    2. Moderate trophoblastic proliferation
    3. Karyotype: Triploid (69XXX or 69XXY)
      1. Fertilization by more than one sperm
    4. Malignant change less likely than in complete mole
  • Symptoms
  1. Vaginal Bleeding during pregnancy in 3rd-4th month
  2. Hyperemesis Gravidarum
  3. Passage of grapelike villi from the Uterus
  4. Abdominal Pain early in pregnancy
  5. Pallor or Dyspnea
    1. Associated with Anemia
  6. Anxiety and Tremor
    1. Due to weak Thyroid stimulation by HCG
  • Signs
  1. Excessive Uterine enlargement
    1. Larger than expected for Gestational age
  2. Fetus absent
    1. Fetal Heart Tones absent
    2. Absent fetal parts
  3. Ovarian enlargement (10%)
    1. Related to theca-lutein cysts
  4. Onset Hypertension early in pregnancy
    1. Occurs before Pregnancy Induced Hypertension
    2. Occurs in first or second trimester
  • Histology
  1. Gross Examination
    1. Whitish grape-like cluster
    2. Interspersed blood clots
  2. Microscopic changes of villi
    1. Trophoblastic proliferation
      1. Cytotrophoblast (Langerhans Cell) proliferation
        1. Cuboid cells
        2. Prominent nuclei
      2. Syncytiotrophoblast proliferation
        1. Sheets of cytoplasm proliferate
        2. Dark oval nuclei
    2. Hydropic changes to central stroma
      1. Cystic spaces form (cisterns)
      2. Avascular edematous spaces form
    3. Fetal Vessels absent
  • Labs
  1. Quantitative bhCG
    1. Excessively elevated above expected levels
    2. Level may exceed 1 Million IU
    3. Directly reflects tumor volume
  2. Complete Blood Count
    1. Anemia
    2. Platelets decreased
  3. Liver Function Testing
  4. Thyroid Function Testing
    1. Thyroid Stimulating Hormone
    2. Free T4
  • Radiology
  1. Molar Pregnancy screening: Pelvic Ultrasound
    1. Mass of Vesicles appears like snowstorm
    2. Differential diagnosis
      1. Septic Abortion
      2. Fibroma
  2. Molar Pregnancy confirmed
    1. Chest XRay
    2. Consider CT Head and Abdomen
  • Complications
  1. Malignant transformation to Choriocarcinoma in 10-20%
    1. Locally Invasive Mole: Chorioadenoma destruens (66%)
    2. Gestational Choriocarcinoma (33%)
  2. Hyperthyroidism
  3. Pregnancy Induced Hypertension
  • Management
  1. Evacuation of Uterus
    1. Dilatation and Evacuation
    2. Dilatation and Curettage
  2. Avoid Hysterectomy, Hysterotomy, or Pitocin
    1. Increased risk of metastasis (Relative Risk: 3.0)
    2. Clamp uterine vessels early if Hysterectomy needed
  3. Chemotherapy Indications after D&C
    1. Quantitative bhCG persistently elevated
    2. Persistent uterine bleeding
    3. Evidence of trophoblastic metastasis
      1. Brain
      2. Lungs
  • Monitoring
  1. Follow Quantitative bhCG levels until 0
  2. Serial bHCG for 6 months to 1 year
    1. Use Contraception during this time
  3. Chemotherapy if bHCG rises or does not fall to 0
    1. Methotrexate usually used
  • Prognosis
  1. Recurrence rate of complete mole: 20%
    1. May recur as locally invasive or metastatic
  2. Recurrence rate in future pregnancies: 1-2%
  • References
  1. Stenchever (2001) Comprehensive Gynecology, p. 1047-62
  2. Shapter (2001) Obstet Gynecol Clin North Am 28(4):805 [PubMed]