A 28-year-old pregnant woman at 14 weeks gestation has markedly elevated beta-hCG levels (over 100,000 mIU/mL). Ultrasound shows a 'snowstorm' appearance with no fetal parts. Histology shows diffuse hydropic villi with circumferential trophoblastic hyperplasia. Which is the karyotype of this lesion?
- A 45,XO
- B 69,XXY
- C 46,XX (all paternal) ✓
- D 46,XY
Correct answer: C. 46,XX (all paternal)
Explanation
Complete hydatidiform mole shows diffuse hydropic villi, circumferential trophoblastic hyperplasia, absent fetal parts, and markedly elevated beta-hCG. Karyotype is 46,XX (or rarely 46,XY), entirely of paternal origin (androgenesis). Partial mole is triploid (69,XXY) and shows two populations of villi with fetal parts. 45,XO is Turner syndrome. 46,XY normal karyotype does not fit this presentation.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.