First identified in the pancreas as autoimmune pancreatitis, the IgG4-related disease is now known to affect many organs and body sites. Renal involvement may present as a discrete mass noted radiologically, or patients may present with renal failure secondary to diffuse sclerosing tubulointerstitial disease. Patients often have laboratory abnormalities that can support the diagnosis such as eosinophilia, low complement and hypergammaglobulinemia with an elevation of serum IgG4 levels. A combination of imaging, clinical and laboratory features, and histology are needed to make a definitive diagnosis. Patients often show a clinical and radiographic response to steroid therapy. The Jones methenamine silver stain here shows the classic fibro-inflammatory pattern seen in this disease. This patient also had positive IgG staining in glomeruli in a membranous pattern. Membranous glomerulopathy is the most commonly described glomerular feature in IgG4-related disease and this has been shown to be PLA2R negative in a small case series (see references).
References:
Saeki T, Kawano M, et al. The clinical course of patients with IgG4-related kidney disease. Kidney International 2013 84:826–833.
Cornell LD. IgG4-related kidney disease. Curr Opin Nephrol Hypertens 2012 21:279-288.
Alexander MP, Larsen CP, et al. Membranous glomerulonephritis is a manifestation of IgG4-related disease. Kidney International 2012 83:455-462.
Raissian Y, Nasr SH, et al. Diagnosis of IgG4-related tubulointerstitial nephritis. J Am Soc Nephrol. 2011 Jul;22(7):1343-52.
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