Complete hydatidiform mole (CHM) is distinguished from partial mole (PHM) in which of the following sets of features?
- A CHM: 69XXX triploid; some fetal parts present; swiss-cheese appearance on ultrasound; lower risk of GTN
- B CHM: 46XX diploid androgenetic; snowstorm appearance; no fetal parts; higher risk of persistent GTN (15–20%) ✓
- C CHM: biparental diploid 46XX; fetal parts occasionally present; 5% risk of choriocarcinoma
- D CHM: always 46XY; entirely paternal origin; presents only in first trimester
Correct answer: B. CHM: 46XX diploid androgenetic; snowstorm appearance; no fetal parts; higher risk of persistent GTN (15–20%)
Explanation
Complete hydatidiform mole is characterised by: completely androgenetic diploid karyotype (46XX in 85%, 46XY in 15%) derived from two paternal haploid contributions with loss of maternal chromosomes; no fetal/embryonic tissue; diffuse hydropic villi; classic 'snowstorm' ultrasound; and a 15–20% risk of persistent GTN (invasive mole/choriocarcinoma). Partial mole is typically triploid (69XXX or 69XXY), has biparental origin with one maternal + two paternal sets, has focal molar change with fetal/embryonic parts, has a 'swiss cheese' appearance, and carries only 0.5–5% GTN risk.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.