Development of IgA nephropathy 14 years after diagnosis of membranous nephropathy.

Membranous nephropathy is characterized clinically by nephrotic proteinuria and pathologically by the presence of electron dense IgG deposits below the epithelium in glomerular basement membrane. Although about 20–30% of cases of membranous nephropathy are secondary, the majority of cases are idiopathic. The clinical features of IgA nephropathy include haematuria and proteinuria. Although IgA nephropathy is frequently accompanied by IgG and C3 deposits on histopathological examination, IgA deposits are observed predominantly in the mesangial area. The exact pathogenic mechanisms of membranous nephropathy and IgA nephropathy have not yet been fully identified. Several cases of overlapping membranous and IgA nephropathy have been reported w1–8x, but the diagnosis of both conditions was made simultaneously on renal biopsy. Therefore, it is not clear whether the two diseases develop simultaneously or at different time points. In this report, we describe a 57-year-old female patient who developed IgA nephropathy 14 years after being diagnosed with membranous nephropathy.