SAT241 Severe Hypercalcemia Secondary To Likely Sarcoidosis

Disclosure: N. Nair: None. A 42 year old gentleman with no known past medical history initially presented to the Endocrinology office referred from his primary care provider for the evaluation of severe hypercalcemia. He initially presented to his PCP with 8 months of progressive tachycardia, shortness of breath and persistently elevated blood pressures but was noted with a serum calcium of 14.9. On my initial evaluation, patient was well appearing, tachycardic with normal rate and rhythm with otherwise no abnormal findings. His blood pressure was elevated to 150s systolic from a baseline of less than 120. Based on the severity of the initial hypercalcemia, an extensive workup was sent to rule out potential etiologies for his hypercalcemia including Vitamin D, PTH, PTHrp, serum free and light chains, CMP, ionized calcium, and serum protein electrophoresis. The initial workup revealed a calcium improved to 12.1 from the initial 14.9, with significant elevation in ionized calcium. PTH and 25 hydroxyvitamin D were suppressed, ruling out primary hyperparathyroidism. Interestingly, 1,25 dihyroxyvitamin D levels were within the upper limit of normal, raising the possibility of granulomatous disease. PTHrp was elevated. Serum protein electrophoresis had revealed mild elevations in beta immunoglobulins. Based on the findings of the initial workup, concern remained for granulomatous disease and malignancy, and a CT of the chest, abdomen and pelvis was ordered. CT showed bilateral perihilar interstitial nodules, mildly enlarged mediastinal and hilar lymph nodes, and splenomegaly with ill defined splenic lesions. No mass or tumor was identified in this study. Although the potential for monoclonal gammopathies and malignancy remain in the differential diagnosis, his presentation, CT scan, and lab findings may be explained by sarcoidosis. While the normal 1,25 Vitamin D levels in the setting of suppressed PTH and 25 Vitamin D may be more classically associated with granulomatous disease, significant renal impairment, elevations in PTHrp and immunoglobulins are not uncommon, making sarcoidosis a likely explanation for his symptoms short of obtaining a biopsy. He was subsequently referred to pulmonology to evaluate for sarcoidosis and to oncology to evaluate further the elevations in serum immunoglobulins. This patient presentation is unique as it is not common to encounter cases of severe hypercalcemia in the outpatient setting. Here, it is important to note that PTHrp elevations and elevations in light chains may be seen in sarcoidosis as well as malignancy. This case illustrates the importance of a wide differential diagnosis in order to avoid the pitfall of prematurely determining a working diagnosis. Presentation: Saturday, June 17, 2023