GTD

• Gestational trophoblastic disease (GTD)


  Term used to encompass a group of tumors typified by abnormal trophoblast proliferation
• Trophoblast


  Produces human chorionic gonadotropin (hCG)
• Hydatidiform mole


  Characterized by the presence of villi
• Nonmolar trophoblastic malignant neoplasms

  Lack villi
• Types of hydatidiform moles

  • Complete hydatidiform mole
  • Partial hydatidiform mole
  • Invasive mole
• Types of nonmolar trophoblastic neoplasms

  • Choriocarcinoma
  • Placental site trophoblastic tumor
  • Epithelioid trophoblastic tumor
• Gestational trophoblastic neoplasia (GTN)

  Malignant forms of GTD
• GTN includes invasive mole, choriocarcinoma, placental site trophoblastic tumor, and epithelioid trophoblastic tumor
• GTN develops weeks or years following any type of pregnancy, but more frequently follows hydatidiform mole
• GTN is often managed as a single composite clinical entity
• With chemotherapy, most GTN tumors are highly curable
• Complete hydatidiform mole


  • Gross specimen with characteristic vesicles of variable size
  • Generalized edema and cistern formation within avascular villi
  • Haphazard trophoblastic hyperplasia
• Features used to classify hydatidiform moles


  • Degree of histological changes
  • Karyotype
  • Immunostaining differences
  • Absence or presence of embryonic elements
• Differences between partial and complete hydatidiform moles

  • Karyotype
  • Clinical presentation
  • Diagnosis
  • Uterine size
  • Theca-lutein cysts
  • Initial hCG levels
  • Medical complications
  • Rate of subsequent GTN
  • Pathology
• Ethnic predisposition is seen with hydatidiform mole, with higher prevalences in Asians, Hispanics, and American Indians
• The incidence of hydatidiform mole in the US and Europe is relatively constant at 1 per 1000 deliveries
• Strongest risk factors for hydatidiform mole

  • Age
  • Prior hydatidiform mole
• With a prior complete mole, the risk of another mole is 0.9%, and with a previous partial mole, the rate is 0.3%
• After two prior complete moles, approximately 20% of women have a third mole
• Pathogenesis of complete mole

  1. Ovum fertilized by haploid sperm, which then duplicates its own chromosomes

  2. Less commonly, fertilization by two sperm (dispermy)
• Pathogenesis of partial mole

  Two sperm fertilize a haploid egg, resulting in a triploid zygote
• Rarely, a twin pregnancy may have one chromosomally normal fetus paired with a complete diploid molar pregnancy
• Complications of twin pregnancy with a molar component

  • Thyrotoxicosis
  • Preeclampsia
  • Hemorrhage
• Survival of the normal fetus in a twin pregnancy with a molar component varies and depends on associated comorbidity from the molar component
• Most evidence indicates no significant difference in risk of subsequent GTN between women who continue or terminate a twin pregnancy with a molar component
• Clinical findings in molar pregnancy

  • Uterine growth exceeding expectation
  • Softer uterus
  • Absent fetal heart motion with complete mole
  • Theca-lutein cysts in the ovaries
• Theca-lutein cysts regress following pregnancy evacuation and subsequent hCG level decline, so expectant management is preferred
• Elevated serum free thyroxine (fT4) and decreased thyroid-stimulating hormone (TSH) levels are common due to the thyrotropin-like effects of hCG, but clinically apparent thyrotoxicosis is unusual
• 12.31 cm
• XRT OVARY_H
• =7.24 cm
• FIGURE 13-3 Sonogram of an ovary with multiple theca-lutein cysts in a woman with a complete hydatidiform mole.
• Theca-lutein cysts


  • More common with a complete mole
  • Likely result from ovarian overstimulation by excessive hCG levels
• hCG and luteinizing hormone share the same receptor, and both can stimulate the theca layer that surrounds follicles
• Theca-lutein cysts


  Regress following pregnancy evacuation and subsequent hCG level decline
• Expectant management is preferred for theca-lutein cysts
• Occasionally, a larger cyst may undergo torsion, infarction, and hemorrhage
• Oophorectomy is not performed unless extensive infarction persists after untwisting
• Thyrotoxicosis


  • Unusual with molar pregnancies
  • Can be mimicked by bleeding and sepsis from infected products
  • Serum free T4 levels rapidly normalize after uterine evacuation
• Cases of presumed "thyroid storm" have been reported with molar pregnancies