Immunoglobulin A nephropathy with superimposed minimal change disease complicated by acute kidney injury requiring temporary hemodialysis.

Immunoglobulin A (IgA) nephropathy (IgAN) with superimposed minimal change disease (MCD) is a rare but increasingly recognized clinicopathological phenotype that is generally associated with a favorable renal prognosis. We present a case of IgAN with MCD complicated by severe acute kidney injury (AKI) during the clinical course and requiring temporary renal replacement therapy. A 38-year-old man presented with acute nephrotic syndrome. Renal biopsy showed mesangial IgA deposition, and anti-galactose-deficient IgA1 antibody (KM55) staining demonstrated co-localization with IgA deposits, supporting the diagnosis of IgAN with superimposed MCD. Electron microscopy revealed foot process effacement, leading to a diagnosis of IgAN with MCD. High-dose prednisolone therapy was initiated; however, the patient subsequently developed severe AKI requiring hemodialysis (HD). Concurrent treatment with cyclosporine A and steroid pulse therapy was administered, ultimately allowing successful discontinuation of HD. This rare case was diagnosed as IgAN with MCD based on mesangial IgA deposition supported by KM55 staining and characteristic electron microscopic findings, and this case demonstrates that severe AKI requiring temporary HD may occur during the clinical course of IgAN with MCD. Although IgAN with MCD has been increasingly recognized, reports of cases complicated by severe AKI requiring HD remain limited in the literature. This patient showed subsequent improvements in renal function and proteinuria, suggesting that this condition may be reversible. These findings highlight the importance of careful clinical management with attention to the potential risk of AKI even in patients with IgAN with MCD.