Regarding the heterogeneity of gestational trophoblastic disease, a 40-year-old woman develops GTN 14 months after a term pregnancy (non-molar). Her WHO/FIGO score is calculated at 9 (high-risk). Which factor specifically differentiates the gestational origin of this trophoblastic tumor from a primary choriocarcinoma arising from ovarian germ cells?
- A Elevated beta-hCG (choriocarcinoma from any origin produces hCG equally)
- B Presence of both cytotrophoblast and syncytiotrophoblast cells on histology
- C Response to chemotherapy (gestational choriocarcinoma is more chemo-sensitive)
- D DNA analysis showing paternal (biparental) DNA in addition to maternal DNA, confirming gestational origin ✓
Explanation
Gestational choriocarcinoma (arising from any pregnancy—term, molar, ectopic) contains biparental genetic material (maternal + paternal DNA) because it originates from fertilization. Primary ovarian choriocarcinoma (a germ cell tumor) contains only maternal haploid DNA in its component cells (androgenetic origin is absent). This distinction is made by genotyping/DNA analysis using microsatellite markers or comparative genomic hybridization to demonstrate the presence of paternal alleles in gestational cases. Clinically, this distinction matters because gestational choriocarcinoma responds much better to chemotherapy and has near-100% cure rates with EMA-CO, while ovarian germ cell choriocarcinoma is more chemoresistant. Histology alone cannot distinguish them.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.