Progressive kidney failure as the sole manifestation of extrapulmonary sarcoidosis.

Sarcoidosis is a chronic multisystem disorder characterized by an accumulation of T lymphocytes and mononuclear phagocytes, non-caseating epitheliod granulomas and derangement of normal tissue architecture in affected organs. Sarcoidosis can affect any organ system, however approximately 90% of patients with sarcoidosis have pulmonary, lymph node, cutaneous or ocular manifestations. Renal involvement in sarcoidosis is rare and clinically significant renal dysfunction even less common. We present a case of isolated renal sarcoidosis which manifested with progressively worsening renal function and hypercalcemia. A systematic diagnostic approach with pertinent laboratory studies, imaging and renal biopsy elucidated the diagnosis of renal sarcoidosis without any evidence of systemic involvement.