Renal Sarcoidosis Mimicking Tubulointerstitial Nephritis and Uveitis Syndrome: A Case with Granulomatous Renal Vascular-Wall Involvement

Renal sarcoidosis and tubulointerstitial nephritis and uveitis (TINU) syndrome can involve both the kidneys and eyes. Accurate diagnosis becomes more difficult when clinical clues of sarcoidosis are absent or limited; thus, careful diagnosis with sampling or organ biopsy is required. We report a 77-year-old man with prior ophthalmologic inflammatory disease who presented with bilateral visual impairment, fatigue, anorexia, edema and acute kidney dysfunction. While computed tomography showed no abnormalities and plasma ACE levels were normal, kidney biopsy showed tubulointerstitial nephritis with non-necrotizing epithelioid granulomas in small-vessel walls, favoring renal sarcoidosis over TINU. Kidney function improved with the reduction in c-reactive protein levels following the initiation of glucocorticoid treatment. Granulomatous involvement of small-vessel-walls may provide a histologic clue favoring renal sarcoidosis over TINU.