Renal Sarcoidosis Presenting as Acute Kidney Injury With Persistent Hypercalcemia in the Absence of Respiratory Symptoms: A Report of a Rare Case.

Sarcoidosis is a chronic multisystem granulomatous disease of unknown etiology, known for its diverse manifestations and ability to mimic other pathologies. Renal involvement in sarcoidosis is uncommon. We present a diagnostically challenging case of a 66-year-old male who presented with unintentional weight loss, anorexia, and lethargy, having acute kidney injury (AKI) and refractory hypercalcemia, ultimately diagnosed with renal sarcoidosis. This report underscores the significance of maintaining a broad differential diagnosis in cases of unexplained AKI and hypercalcemia, especially in the absence of respiratory symptoms. Early recognition of key imaging and biochemical clues allows prompt initiation of therapy and helps optimize patient outcomes.