ODP093 Hunt for Hypercalcemia

Hypercalcemia is a relatively common clinical problem. Among all causes of hypercalcemia, primary hyperparathyroidism and malignancy are the most common. This case highlights the importance of collaboration between subspecialists to identify the etiology of a patient's hypercalcemia. A 71-year-old male with history of tobacco use and untreated hepatitis C, presented to the emergency department with several weeks of progressively painful, non-traumatic right upper extremity (RUE) swelling. Chest CT showed a 1.4 cm right axillary lymph node and the patient was referred to general surgery for a biopsy which was deferred due to size. Due to worsening lymphedema, the patient underwent a venogram with plans for a lymphedema pump, however in the interim he presented with worsening RUE edema. Labs were notable for Ca 12.7 mg/dL(8.6-10.3) though the patient reported taking chlorthalidone and calcium-based antacids. The patient was admitted with lymphedema progression and new-onset hypercalcemia. Labs were significant for suppressed PTH 6.8 pg/ml(10-66), undetectable PTHrP, Vit D 9.9 ng/mL(32-100), 1,25-Vit D 110 pg/mL(19.9-79.3), and SPEP/UPEP without an M-spike. Additional labs included PSA 17.96 ng/mL(0-3.9) and LDH 3471 units/L(94-260). Chest CT demonstrated a few sub-centimeter calcified pulmonary nodules with the appearance of chronic granulomas, but no evidence of hilar or mediastinal lymphadenopathy, significantly reducing the likelihood of sarcoidosis. RUE CT showed cortical destruction of the humeral head and proximal shaft, along with infiltrative enlargement of the muscles. There were also a few enlarged axillary lymph nodes, the largest measuring 2 cm. The patient was hydrated with initial improvement of his labs however calcium subsequently increased to 13.5 mg/dL. Due to concern for 1,25-Vit D mediated hypercalcemia and the source still unknown, the patient was started on prednisone 20 mg with normalization of the calcium level. An excisional lymph node biopsy followed by flow cytometry confirmed the diagnosis of diffuse large B cell lymphoma(DLBCL). The patient was treated with chemotherapy and had since been in remission. Of note the patient was also found to have localized prostate cancer treated with external beam radiation . Hypercalcemia is estimated to occur in approximately 30% of patients with malignancy and is associated with a poorer prognosis. Mechanisms include humoral hypercalcemia (PTHrP), osteolytic cytokine production, extensive bone metastasis in the absence of excess osteolytic factors, and production of 1,25-Vit D. Our patient had several risk factors for hypercalcemia including thiazide and antacid use, which may cause milk-alklai syndrome; an elevated PSA, which was eventually confirmed to be prostate cancer; and an elevated 1,25-Vit D of unknown etiology. Due to the risks associated with hypercalcemia and after extensive conversations amongst the subspecialists, the decision was made to start empiric treatment with prednisone. Eventually the patient underwent CT guided biopsy confirming the diagnosis of DLBCL, but it was a "hunt". Presentation: No date and time listed