Idiopathic granulomatous interstitial nephritis responsive to mycophenolate mofetil therapy.

Granulomatous interstitial nephritis (GIN) is a rare histologic disease. Various causes have been reported in the literature, including drugs, sarcoidosis, and infections. Other incidents have no discernible cause and are identified as idiopathic. We report a 68-year-old white man who presented with acute kidney injury and was given a diagnosis of idiopathic GIN. Mycophenolate mofetil treatment was elected because of steroid toxicity. He responded well to mycophenolate mofetil and has been in remission for more than 3 years. To our knowledge, this is the first report of successful treatment with mycophenolate mofetil of an adult patient with idiopathic GIN.