Granulomatous interstitial nephritis: a complication of heroin abuse

A 27-year-old man, a known heroin addict with previously diagnosed nephrotic syndrome, had a percutaneous renal biopsy for recurrent proteinuria. The biopsy revealed a glomerular lesion compatible with focal sclerosing hephropathy. The renal interstitium also demonstrated numerous active granulomas characterized by the presence of both multilamellated basophilic material and areas of unstained fibrillar material. These findings represent a previously undescribed complication of parenteral heroin abuse--renal granuloma formation.