Three cases of urolithiasis associated with sarcoidosis: a review of Japanese cases.

We report three cases of urolithiasis associated with sarcoidosis and reviewed the Japanese published reports. All cases had hypercalcemia, hyperuricemia, hypercalciuria and renal dysfunction. A serum level of 1,25-(OH)2D3 was elevated and intact parathyroid hormone (PTH) was decreased. Stone components were predominantly calcium oxalate. Abnormal calcium metabolism is a well-known feature of sarcoidosis and the reported prevalence of urolithiasis in patients with sarcoidosis was 1.3-14.0% in the English published reports. However, urolithiasis associated with sarcoidosis is uncommon in Japan and we could find only 16 documented cases including ours. Abnormal calcium metabolism is caused by an increase in serum concentration of 1,25-(OH)2D3, which is derived from endogenous overproduction in the pulmonary macrophages. If patients with urolithiasis have abnormal calcium metabolism, renal impairment and suppression of PTH, the possibility of sarcoidosis should be considered for a differential diagnosis. Also, it should be emphasized that the presence or developing of urolithiasis is to be monitored during follow up of patients with sarcoidosis.