Podocytic Infolding Glomerulopathy in a Patient with Phospholipase A2 Receptor-Positive Membranous Nephropathy and Review of the Literature.

Podocytic infolding glomerulopathy (PIG) is a rare diagnosis based on characteristic histopathologic findings on renal biopsy and was proposed as a new entity about a decade ago. It is a type of podocytic injury, characterized by invagination of the podocyte cell membrane (cytoplasmic projections from podocytes) into the glomerular basement membrane. The presence of microspheres and/or microtubules on electron microscopy is the characteristic finding. PIG is most often associated with autoimmune conditions like systemic lupus erythematosus. We report pathologic findings typical of PIG in a patient with phospholipase A2 receptor antibody-positive membranous nephropathy. She was treated with rituximab and responded well with decrease in proteinuria to the sub-nephrotic range.