Granulomatous interstitial nephritis in extrapulmonary sarcoidosis.

Sarcoidosis is a multisystem disorder in which the lungs or intrathoracic lymph nodes are involved in more than 90% of patients with the disease. It occasionally involves kidneys most commonly due to disordered calcium metabolism. Granulomatous interstitial nephritis is a distinct renal pathology in sarcoidosis. Renal dysfunction due to granulomatous interstitial nephritis is rare. We recently encountered a sarcoidosis patient without hypercalcemia and any evidence of pulmonary involvement which is distinctly unusual.