Chronic Tubulointerstitial Nephritis Presenting as Multiple Renal Nodules and Pancreatic Insufficiency

We report a case of chronic tubulointerstitial nephritis associated with multiple nodular lesions of the kidneys in a patient with autoimmune pancreatitis. Serum immunoglobulin G4 (IgG4) level was increased, and immunohistochemical staining for IgG4 on the renal biopsy specimen showed positive staining of plasma cells and tubular basement membrane within areas of chronic tubulointerstitial nephritis. There are a few reports of nodular lesions of kidneys or interstitial nephritis associated with autoimmune pancreatitis. Our case is unique in that all 3 conditions presented together and suggests that interstitial nephritis can present as nodular lesions.