Coexisting primary hyperparathyroidism and sarcoidosis cause increased angiotensin-converting enzyme and decreased parathyroid hormone and phosphate levels.

CONTEXT: Primary hyperparathyroidism (PHPT) and sarcoidosis may separately contribute to abnormal calcium and phosphate metabolism via different mechanisms, and their coexistence is infrequently reported.

OBJECTIVE

We sought to characterize a group of 50 patients with coexisting PHPT and sarcoidosis in our institution to evaluate their clinical and laboratory characteristics.

DESIGN AND

SETTING

This was a retrospective observational study of patients with both disorders at our institution between January 1980 and December 2011.

OUTCOME: A cohort of 50 patients was identified, with mean ± SD age 59.6 ± 13.9 years and 86% women. Serum calcium in the cohort was 11.1 ± 1.1 mg/dL, phosphate was 3.3 ± 0.6 mg/dL, and PTH was 76 ± 42 pg/mL. Serum 25-hydroxyvitamin D was 25 ± 9 ng/mL, and serum 1,25-dihydroxyvitamin D was 51 ± 20 pg/mL; 24-hour urine calcium was 275 ± 211 mg. In subjects with sarcoidosis, serum angiotensin-converting enzyme (ACE) was 47.2 ± 37.4 U/L. Sarcoidosis was diagnosed first in 50% of patients, PHPT was diagnosed first in 16% of patients, and sarcoidosis and PHPT were both diagnosed within 6 months of each other in 30% of patients. The interval between the 2 diagnoses when sarcoidosis was diagnosed first was 15.5 ± 12.4 years and was 5.5 ± 6.0 years when PHPT was diagnosed first. Patients with PHPT who had active sarcoidosis had higher serum ACE levels (60.9 ± 38.1 vs 20.2 ± 14.0 U/L, P <.0001), lower PTH levels (60 ± 24 vs 96 ± 41 pg/mL, P = .01), and lower phosphate levels (2.7 ± 0.6 vs 3.2 ± 0.5 mg/dL, P = .02).

CONCLUSIONS

Fifty patients with coexisting PHPT and sarcoidosis are described, with patients with PHPT coexisting with clinically active sarcoidosis having increased serum ACE levels and decreased serum PTH and phosphate levels compared with those with inactive sarcoidosis.