Exceptional Case Development of IgG4-related disease in a patient diagnosed with idiopathic membranous nephropathy

We report a case of IgG4-related disease (IgG4-RD) diagnosed after 3 years of follow-up for idio-pathic membranous nephropathy (MN). MN has been considered as glomerular lesion of IgG4-related kidney diseases in recent years and was diagnosed simultaneously with or after a diagnosis of IgG4-RD in previously reported cases. In the present case, IgG4-RD developed 3 years after the diagnosis of idiopathic MN, indicating a possible relationship between idiopathic MN and IgG4-RD through common underlying mechanisms of development