Concurrent Giant Cell Arteritis and Anti-PLA2R-Positive Membranous Nephropathy: A Case Report

Background: Giant cell arteritis (GCA) is a vasculitis mostly affecting older people. Primary membranous nephropathy (MN) is an immune-mediated glomerulopathy recently shown to be caused by autoantibodies. We report a case of both illnesses in an older gentleman. Case Presentation: A 63-year-old man developed systemic inflammatory signs and symptoms and near simultaneous nephrotic-range proteinuria. Investigations demonstrated both giant cell arteritis (GCA) and membranous nephropathy, with the presence of the M-type phospholipase A2 receptor (PLA2R) within subepithelial immune deposits. Renal function remained normal throughout the course. The patient achieved complete clinical and biochemical remission of both illnesses coincident with corticosteroid therapy. Conclusions: Although rare cases of concurrent GCA and MN have been reported, GCA occurring with PLA2R-positive MN has not been documented. This case raises the possibility of overlapping immunological pathways and may offer clues to the pathogenesis of GCA.