Defective placentation in pre-eclampsia results from failure of extravillous cytotrophoblast invasion. Which histological finding in the spiral arteries best reflects this defect?
- A Persistence of the musculoelastic layer of the spiral arteriolar wall, with fibrinoid necrosis and lipid-laden foam cells (acute atherosis) ✓
- B Complete physiological conversion of spiral arterioles into flaccid dilated vessels
- C Hypertrophy of the tunica media with compensatory luminal dilation
- D Neutrophilic vasculitis of the decidual vessels with karyorrhexis
Correct answer: A. Persistence of the musculoelastic layer of the spiral arteriolar wall, with fibrinoid necrosis and lipid-laden foam cells (acute atherosis)
Explanation
In normal pregnancy, endovascular trophoblast replaces the endothelium and destroys the musculoelastic media, converting spiral arteries into low-resistance flaccid vessels. In pre-eclampsia this conversion is shallow and incomplete: the muscular wall persists, resistance stays high, and the vessel may show fibrinoid necrosis with foam cells, termed acute atherosis. This explains the raised placental resistance seen on uterine artery Doppler in affected pregnancies.
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.