Acute kidney injury in a patient with sarcoidosis: hypercalciuria and hypercalcemia leading to calcium phosphate deposition.

Sarcoidosis can affect kidney function through many different mechanisms. We present a patient with sarcoidosis who developed acute kidney injury (AKI). He had a high 1,25-OH vitamin D level and hypercalciuria. As his renal function declined he developed hypercalcemia. A kidney biopsy showed acute tubular necrosis (ATN) with giant cell formation around calcium phosphate crystals. Calcium phosphate deposition is uncommon in sarcoid. We speculate that early interstitial calcium phosphate deposition may in time lead to the development of Randall's plaques and to the more typical calcium oxalate nephrolithiasis seen in sarcoidosis.