Glomerular endotheliosis in a pregnant woman with severe gestational proteinuria

Preeclampsia is the most common hypertensive disorder to occur during pregnancy. A healthy 38-year-old primipara presented with pretibial edema at 33 weeks of gestation followed by the development of proteinuria at 36 weeks of gestation. She had no past medical history of hypertension and was normotensive during gestation. Her proteinuria persisted after delivery, and she was also hypoalbuminemic. A renal biopsy revealed a remodeling of the glomerular basement membrane (GBM) with double contours. Some of the glomerular segments showed endothelial swelling. Immunoperoxidase staining for C4b-binding protein was positive and Protein S was weakly detected in the GBM. Electron microscopy revealed an expansion of the subendothelial zone as well as mesangial cell interposition. This case suggests that glomerular endotheliosis may therefore sometimes be present despite the absence of hypertension.