Membranous nephropathy with solitary immunoglobulin A deposition.

A 71-year-old woman was admitted with nephrotic syndrome. Light and electron microscopic analyses of renal biopsy tissue showed typical diffuse membranous features. In contrast, granular deposition of immunoglobulin A (IgA), but not IgG, IgM, C3 or C1q, was observed along the capillary walls on immunofluorescence. The patient was pathologically diagnosed with diffuse membranous nephropathy with solitary IgA deposition. Secondary membranous nephropathy was suspected; however, no underlying cause was found. The clinical and pathological findings, except for those of immunofluorescence, were all compatible with a diagnosis of primary membranous nephropathy. This is the first reported case of membranous nephropathy associated with solitary IgA deposition.