Sarcoidosis is a systemic disease of middle-aged patients, with an incidence of 15-20 per 100,000. African Americans are affected much more commonly than those of European ancestry, with the exception of increased incidence in patients of Scandinavian ancestry; there is a slight female preponderance. Organs most commonly involved include lung, lymph nodes (particularly hilar), eyes, and skin. Kidney disease develops in up to a third of patients, and may present as acute kidney injury related to hypercalcemia, or GFR decline and low-level proteinuria due to granulomatous parenchymal injury.