A curious case of hypercalcemic crisis in sarcoidosis: The missing link beyond 1,25(OH)D.

Sarcoidosis is a chronic granulomatous disease affecting various organs and is one of the causes of parathyroid hormone (PTH)-independent hypercalcemia. However, sarcoidosis presenting with severe hypercalcemia is very rare. We present a case with an initial presentation of hypercalcemic crisis (corrected calcium of 16.8 mg/dl) and suppressed iPTH (7.2 pg/ml). Upon thorough evaluation, including biochemical, radiology, and histopathology, of the right inguinal lymph node biopsy, extrapulmonary sarcoidosis was diagnosed. The patient was initiated on glucocorticoid therapy, leading to clinical and biochemical improvement. This case is characterized by hypophosphatemia and inappropriately normal 1,25-dihydroxy vitamin D level, a finding rarely reported in the literature. Hypercalcemia may be due to the overproduction of bone-resorbing cytokines, INF-α, IL-6, IL-1β, and PTHrP.