Membranous Nephropathy

Clinical History:  60 year old male with edema and nephrotic range proteinuria (>3.5 grams per 24 hours).Also found to have elevated lipids and decreased albumin.  Clinical diagnosis of nephrotic syndrome was made (proteinuria, hyperlipidemia, and hypoalbuminemia).  

Differential diagnosis includes membranous nephropathy, focal segmental glomerulopathy, minimal change disease, and other sytemic disease like diabetes.  

Renal biopsy shows the following on silver staining:

Notice the small eye-lash like projections form the glomerular basement membranes when cut perpendicular.  The mesangial regions are normal and there is no endocapillary proliferation.  By light microscopy these findings are consistent with membranous nephropathy.

IF studies confirm IgG, kappa, lambda,  and C3 in a glomerular basement membrane distribution.

EM shows dark electron dense deposits in the sub-epithelial space.  Note the severe overlaying foot process effacement.