Renal sarcoidosis with a pseudotumoral pyelic localization

BACKGROUND: Renal sarcoidosis exceptionally presents as a unilateral pyelic pseudotumor as in this case where it was associated with granulomatous nep hropathy. CASE REPORT: A 33-year-old man had a two-year history of systemic sarcoidos is with no renal involvement. He developed renal failure related to interst itial granulomatous nephropathy associated with a pyelic localization leadi ng to unilateral hydronephrosis. Urine drainage associated with corticoster oid therapy provided a favorable course. DISCUSSION: Renal involvement in sarcoidosis is usually the consequence of hypercalcemia and hypercalciuria related to ectopic secretion of calcitriol by the sarcoidosic granulomas, with urinary lithiasis and nephrocalcinosis leading to renal failure and also granluomatous interstitial nephropathy. Glomerulopathy or obstructive nephropathy are rarely reported. Intraluminal localizations such as the pyelic lesion in our case are exceptional but mu st be detected early since they respond to corticosteroid therapy.