IgG4-related Kidney Disease in Which the Urinalysis, Kidney Function and Imaging Findings Were Normal.

IgG4-related kidney disease (IgG4RKD) is recognized as a fibroinflammatory disease characterized by storiform fibrosis, lymphoplasmacytic infiltration and a high serum IgG4 level. A renal biopsy is necessary to diagnose IgG4RKD in patients without any lesions in other organs. Nephrologists typically perform renal biopsies in patients with abnormal urinalysis, such as proteinuria or hematuria, or renal failure. However, we experienced a patient with IgG4RKD without abnormalities in the urinalysis, renal function or imaging, who had severe interstitial lesions. We therefore propose that renal biopsies should be considered if patients do not show abnormal urinalysis findings and are suspected to have IgG4RKD.