Ultrasound at 13 weeks in a 27-year-old woman shows a normally growing fetus with a separate placenta, alongside an enlarged multicystic placental mass. Fetal karyotyping returns 46,XY. Which statement is CORRECT?

• A This represents a partial hydatidiform mole with a triploid fetus
• B The molar tissue is haploid and maternally derived
• C Continuing the pregnancy carries almost no risk of gestational trophoblastic neoplasia
• D The fetus is diploid and the molar tissue is diploid and androgenetic ✓

Explanation

A complete mole coexisting with a normal fetus arises from dizygotic twinning: one conceptus is a normal diploid fetus, the other is a diploid androgenetic complete mole. In a partial mole, by contrast, the single fetus is itself triploid and grossly abnormal. Continuing such a twin pregnancy is possible but carries a substantially elevated risk of gestational trophoblastic neoplasia, requiring close hCG surveillance after delivery.

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.