FRI693 Pthrp Mediated Hypercalcemia In A Patient With Recurrent Hepatocellular Carcinoma

Disclosure: D. Bondarenko: None. M. Ahmad: None. M. Mack: None. P. Ucciferro: None. Background: Humoral hypercalcemia is seen in 30 percent of cancer patients, most commonly driven by parathyroid hormone related peptide (PTHrP) production, osteolytic cytokine production, and 1,25-OH vitamin D production. The most common malignancies associated with PTHrP mediated hypercalcemia are squamous cell carcinomas and breast cancer. Less often hepatocellular cancer presents with hypercalcemia. We describe the case of a patient presenting with hepatocellular carcinoma presenting with recurrent episodes of severe hypercalcemia due to excessive PTHrP production. Clinical Case: The patient was a 68-year-old male with a past medical history of recurrent hepatocellular carcinoma with liver transplant in the past and type 2 diabetes mellitus who presented to the emergency department (ED) for one day of altered mental status. The patient was noted to be extremely agitated and confused by his home health aide and EMS was called. In the ED the patient’s vital signs were as follows: blood pressure of 196/80 mmHg, heart rate of 82 beats per minute, respiratory rate of 18 breaths per minute and temperature of 36.6 degrees Celsius. Initial lab work showed: calcium 13.5 mg/dL, albumin 4.2 g/dL, ionized calcium of 1.63 mmol/L, creatinine 0.99 mg/dL (baseline 0.5 mg/dL), glucose of 438 mg/dL, bicarbonate 23 mmol/L, anion gap 19, and beta hydroxybutyrate 51 mg/dL. Hypercalcemia workup revealed a suppressed PTH of 5 pg/mL (normal 11-67 pg), normal 25-OH vitamin D 43.6 ng/ml (normal 30-100 ng/ml), normal 1,25-OH vitamin D 38 pg/ml (normal 18-72 pg/ml), and elevated PTHrp 36 pg/ml (normal 11-20 pg/ml). The patient was started on aggressive IV fluid resuscitation with normal saline, administered a one-time dose of zoledronic acid and administered a three-day course of calcitonin. For his significant hyperglycemia the patient was started on an insulin infusion and was eventually transitioned to his home basal bolus insulin regimen. On discharge, the patient was scheduled with his oncologist to begin denosumab as an outpatient; however, he chose a palliative approach due to the terminal nature of his disease and recurrent hospitalizations for hypercalcemia. Conclusion: Hypercalcemia of malignancy is common in many different carcinomas with squamous cell cancer, renal cell cancer, breast cancer and multiple myeloma being commonly associated with this phenomenon. Reports of hepatocellular carcinoma associated with hypercalcemia are less common and occur in only 4-8 % of cases. With this case report, we hope to highlight PTHrP as a potential mechanism of humoral hypercalcemia in patients with hepatocellular carcinoma and propose denosumab as a possible treatment for patients with refractory hypercalcemia of malignancy. Presentation: Friday, June 16, 2023