Unexpected hypercalcemia in a diabetic patient with kidney disease.

We report a case of a diabetic patient with progressive chronic kidney disease and unexplained hypercalcemia. This unusual presentation and the investigation of all possible causes led us to perform a renal biopsy. The systemic sarcoidosis diagnosis was confirmed by the presence of interstitial multiple granulomas composed of epithelioid and multinucleated giant cells delimited by a thin fibrous reaction, and by pulmonary computed tomography finding of numerous lumps with ground-glass appearance. Sarcoidosis most commonly involves lungs, lymph nodes, skin and eyes, whilst kidney is less frequently involved. When it affects males it is characterized by hypercalcemia, hypercalciuria, and progressive loss of renal function. Early treatment with steroids allows for a gradual improvement in renal function and normalization of calcium serum values. Otherwise, the patient would quickly progress to end stage renal disease. Finding of hypercalcemia in a patient with renal failure must alert physicians because it may be a sign of several pathological entities.