Unusual glomerulopathy with aggregated subepithelial microspheric particles resembling membranous nephropathy: a variant of glomerulopathy associated with podocytic infolding?

A 69-year-old woman presented with unusual electron microscopic findings. The patient was admitted to ascertain the cause of her persistent proteinuria, and kidney biopsy was performed. While light microscopic findings and immunofluorescence study suggested membranous nephropathy, electron microscopic study showed microspheric particles aggregated in the subepithelial space where electron-dense deposits should have existed. While the microspheric particles could have been unusual and rough deposits, detailed study suggested that the particles could be parts of glomerular podocytes, for example foot processes. This unusual finding was considered as being in a unique clinical course of membranous nephropathy, but a variant of glomerulopathy associated with podocytic infolding, proposed by Joh et al. (J Nephrol 49:61–67, 2007), could not be excluded.