Sarcoid granulomatous nephritis occurring as isolated renal failure

A woman had clinically isolated renal failure caused by granulomatous sarcoid nephritis. At the onset of her illness, there were no historical, physical, or clinical features to suggest a definite causative diagnosis. After a renal biopsy specimen disclosed noncaseating epithelioid granulomas, a course of steroid therapy resulted in prompt disappearance of uremic symptoms and amelioration of her renal failure. Although leukopenia, delayed cellular immunity, and the response to steroids increased the suspicion that the patient had sarcoidosis, it was not until identical granulomas were obtained via mediastinal node biopsy that the diagnosis was confirmed. Sarcoidosis may occur as isolated renal failure. Renal biopsy is indicated to ensure early diagnosis and prompt treatment of this steroid-responsive lesions.