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The disease prevalence is unknown.

The clinical manifestations include tubulointerstitial nephritis (TIN) and membranous glomerulonephritis with or without TIN. Other glomerular disease is reported (IgA nephropathy, membranoproliferative glomerulonephritis, mesangioproliferative glomerulonephritis). Radiological abnormalities include mass lesions and diffusely enlarged kidneys. Presentation may be on routine imaging, with acute or chronic kidney disease, or with nephrosis depending on underlying lesion. Hydronephrosis may occur due to obstruction from IgG4-related retroperitoneal fibrosis.Other extra renal manifestations of IgG4-RD may also be present (e.g. salivary glands, hypophysis, hepatobiliary system, lungs).

The etiology is unknown.

The disease is diagnosed with characteristic imaging and renal biopsy findings (lymphocytic infiltration with predominantly IgG4+ plasma cells, storiform fibrosis, and obliterative phlebitis). Diagnostic criteria have been outlined.

The differential diagnosis depends on presentation. For example, the differential for presentation with TIN includes: medications, autoimmune disease (e.g. Sjogren's syndrome, Sarcoid), malignancy (e.g. lymphoproliferative disease), and infection (e.g. Tuberculosis).

Not supported by randomized controlled trials. Lymphocytic infiltration is usually quickly responsive to steroids. Some patients require immunosuppressants such as Rituximab.

Relapse is common, and progressive renal impairment can occur, including the need for renal replacement therapy.