Sarcoidosis initially manifesting as symptomatic hypercalcemia with the absence of organic involvement

Abstract

A 53-year-old man was admitted to Osaka City University Hospital on July 21, 1998, for investigation of symptomatic hypercalcemia. Laboratory data on admission revealed that serum Ca had increased to around 12.6 mg/dl and there was a significant increase in urinary Ca excretion. The serum phosphate level remained normal. Although the serum PTH level was below the detection limit, serum 1,25-dihydroxyvitamin D (1,25(OH)2D) was increased. Diagnosis of sarcoidosis was supported by a negative tuberculin test and by the elevated levels of serum angiotensin-converting enzyme (ACE), lysozyme activity, and CD4/CD8 ratio in bronchoalveolar lavage specimen; there was however no imaging evidence of sarcoidosis such as bilateral hilar lymphnode enlargement on chest X-ray, high resolution CT or 67Ga citrate scintigraphy. Biopsy specimens from the cervical lymphnode revealed no epitheloid cell granulomas or giant cells. Administration of prednisolone achieved a decrease in serum ACE and 1,25(OH)2D) levels, followed by restoration of serum Ca and urinary Ca excretion to the normal range, and finally by an increase of serum PTH to the normal level. These observations suggested that the hypercalcemia could be explained by extrarenal production of 1,25(OH)2D. We report here on this rare case of sarcoidosis with initial symptoms of symptomatic hypercalcemia resulting from extrarenal production of 1,25(OH)2D.