Uterine evacuation in a 24-year-old woman yields enlarged edematous villi with central cisterns and circumferential trophoblastic proliferation; no fetal tissue is identified. Immunohistochemistry for p57 shows complete absence of staining in the villous stroma and cytotrophoblast. Which genetic constitution explains this result?

• A Tetraploid genome with balanced maternal and paternal contributions
• B Triploid diandric genome with one maternal and two paternal haploid sets
• C Diploid biparental genome with one maternal and one paternal haploid set
• D Diploid androgenetic genome, most commonly 46,XX entirely paternal in origin ✓

Explanation

p57 is a paternally imprinted, maternally expressed gene, so it stains tissue containing a maternal genome. Complete mole is androgenetic (all chromosomes paternal, usually 46,XX by fertilization of an empty ovum followed by duplication), hence p57 negative. Partial mole is triploid diandric and retains maternal genetic material, so it is p57 positive, which excludes option B.

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.