Light microscopy of membranoproliferative glomerulonephritis type II (MPGN with homologous extraglomerular lesions).

A light microscopic study of MPGN identifies three morphologic patterns with homologous extraglomerular lesions. These correspond to reported variants or patterns of MPGN II (Dense Deposit Disease) by electron microscopy. Endomembranous, subendothelial, and holomembranous patterns are described, all with homologous lesions of extraglomerular basement membranes. The holomembranous pattern is morphologically the most unique and may represent a different disease or a subset of MPGN II. The findings are consistent with the definition of MPGN I and II as mesangiocapillary glomerulonephritis and MPGN II as a nephropathic lesion not limited to the glomerular capillary basement membrane (MPGN with homologous extraglomerular lesions).