[Rapidly progressing renal insufficiency as the primary manifestation of systemic sarcoidosis].

Case Report: We report the history of a 67-year-old patient who was admitted to hospital because of rapidly progressive renal insufficiency. The renal biopsy revealed granulomatous interstitial nephritis. The diagnosis of systemic sarcoidosis was confirmed by typical findings of bronchoalveolar lavage and of transbronchial, liver and bone marrow biopsy. Indications for sarcoidosis-related nephrocalcinosis/nephrolithiasis or glomerulonephritis were absent. Simultaneously a monoclonal gammopathy of unknown significance (MGUS) was diagnosed. While the patient having been uremic at the time of diagnosis, the administration of prednisolone effectively improved renal function.

Conclusions: As a rare manifestation of sarcoidosis granulomatous interstitial nephritis can cause rapidly progressive renal insufficiency, which can effectively be treated by steroids, if distinct interstitial fibrosis is absent.