An Unusual Case of Renal-Limited Sarcoidosis Presenting With Hypercalcemia of Unknown Origin: A Case Report

Sarcoidosis is a relatively uncommon multisystem disease that is often difficult to diagnose, frequently requiring multiple physician evaluations. While common symptoms include fatigue, weight loss, lymphadenopathy, and multi-organ involvement, some cases deviate from this classic presentation. We present the case of an elderly male patient who exhibited severe hypercalcemia without the typical systemic manifestations of sarcoidosis. His hypercalcemia of unknown origin led to multiple hospitalizations. Initial medical management provided only temporary relief, and an extensive workup failed to identify a cause. As his condition progressed to acute kidney injury requiring hemodialysis, a more invasive evaluation was pursued. A bone marrow biopsy was unremarkable, but a subsequent kidney biopsy revealed renal-limited sarcoidosis, a rare form of the disease. The patient was started on high-dose corticosteroids, which led to clinical improvement; however, his renal function did not recover sufficiently to discontinue hemodialysis.