IgG4-related tubulointerstitial nephritis and hepatic inflammatory pseudotumor without hypocomplementemia.

Immunoglobulin G4 (IgG4)-related tubulointerstitial nephritis (TIN) is often accompanied by autoimmune pancreatitis (AIP) or chronic sclerosing dacryoadenitis and sialoadenitis. However, IgG4-related TIN without AIP or lacrimal and/or salivary gland lesions has not been well recognized. Here, we report a case of IgG4-related TIN associated with hepatic inflammatory pseudotumor without AIP or lacrimal and/or salivary gland lesions. A 58-year-old Japanese man with epigastralgia underwent contrast-enhanced computed tomography (CT), which revealed multiple low-density lesions in both kidneys and a low density hepatic mass. Laboratory tests showed an extremely high level of serum IgG4. Percutaneous renal and hepatic biopsies showed diffuse infiltration of lymphocytes and IgG4-positive plasma cells with fibrosis in both tissues. Two months after administration of oral prednisolone, both lesions decreased in size on follow-up CT, and the serum creatinine level also improved. No recurrence has been detected for two years with a maintenance dose of prednisolone.