Sjogren's syndrome with acute renal failure caused by renal pseudolymphoma

A 56-year-old man with Sjogren's syndrome was found to have acute renal failure. Immunopathologic analysis of renal biopsy specimens showed polyclonal lymphocytic interstitial infiltration. DNA analysis of the T-cell receptor and the heavy chain immunoglobulin genes showed a polyclonal pattern of gene rearrangements. Renal failure caused by this pseudolymphoma regressed dramatically with steroid therapy. This is the first reported case of proven renal pseudolymphoma that regressed with steroid therapy.