Granulomatous Interstitial Nephritis Due to Renal-limited Sarcoidosis.

Sarcoidosis can present as acute kidney injury (AKI) due to granulomatous interstitial nephritis (GIN). AKI caused by sarcoid GIN without extra-renal manifestations is extremely rare. We report a case of a 42-year-old man with a history of unexplained weight loss admitted with progressively worsening kidney function. Physical examination did not show any abnormality. Laboratory investigations were normal except for high calcium level with no evidence of organ involvement of sarcoidosis. A renal biopsy showed GIN with non-caseating granulomata. Prednisolone was initiated and renal function improved. This is a case of an extremely rare AKI caused by sarcoid GIN without extra-renal manifestations which responded to prednisolone.