Abstract: FR-PO1279
The Last Resort! An Uncommon Case of Refractory Symptomatic Hypercalcemia of Malignancy
Session Information
- Onconephrology: Diagnostic Dilemmas, Therapy-Related Toxicities, and Clinical Cases
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1600 Onconephrology
Authors
- Jayakumar, Vaishnavi, University of South Florida, Tampa, Florida, United States
- Trinh, Anhthu, University of South Florida, Tampa, Florida, United States
- Bassil, Claude, University of South Florida, Tampa, Florida, United States
- Audi, Akram, University of South Florida, Tampa, Florida, United States
Introduction
Hypercalcemia of malignancy (HCM) is a paraneoplastic syndrome associated with significant morbidity and poor prognosis, most commonly seen in solid tumors and less frequently in hematologic malignancies such as chronic lymphocytic leukemia (CLL). Mechanisms include parathyroid hormone-related peptide (PTHrP)–mediated hypercalcemia, osteolytic bone resorption, and excess calcitriol production. Standard management includes aggressive intravenous hydration, calcitonin, and bisphosphonates; however, refractory cases remain a significant therapeutic challenge and are associated with worse outcomes. Although temporizing therapies may reduce serum calcium, definitive control requires treatment of underlying malignancy.
Case Description
A 71-year-old male with CLL on zanubrutinib with disease progression, heart failure (LVEF 25%), and prostate cancer 10 years ago without metastasis treated with radiation therapy and hormonal theray, last PSA 0.03 ng/ml in 2026, recurrent hypercalcemia, presented to the hospital with severe hypercalcemia, fatigue, confusion, constipation and hallucinations. He was found to have calcium 14.8 mg/dL. Workup showed suppressed intact PTH of 8.4 pg/ml , elevated PTHrP of 56.1 and elevated 1,25-vitamin D of 124 pg/ml, consistent with hypercalcemia of malignancy. Thehypercalcemia persisted despite isotonic IV fluids, subcutaneous calcitonin, and IV zoledronic acid. Given inadequate response to conventional therapy, the patient required intermittent hemodialysis for refractory hypercalcemia. Furthermore, denosumab 60 mg subcutaneous was administered, resulting in clinical and biochemical improvement, followed by transient hypocalcemia requiring oral calcium supplementation. The patient was later started on pirtobrutinib for CLL progression. Despite being on cancer therapy, he developed recurrent symptomatic hypercalcemia and ultimately transitioned to hospice care.
Discussion
While sevre hypercalcemia can occur in the setting of malignancy, it is uncommon to encounter refractory hypercalcemia secondary to CLL progression requiring intermittent hemodialysis and denosumab use on top of the conventional medical therapy. Our patient had severe disease and an ongoing tumor-driven pathogenesis. Persistent hypercalcemia despite bisphosphonates should prompt early consideration of adding denosumab therapy, while hemodialysis is reserved for rapid control in severe symptomatic cases.