Introduction: Severe hypercalcemia is a life-threatening metabolic emergency that necessitates prompt initiation of systemic therapy due to the risk of cardiac arrhythmias. It is frequently linked to squamous cell carcinoma through the production of parathyroid hormone–related protein, which mediates the development of humoral hypercalcemia of malignancy. Case: This is a case of a 38-year-old male who was diagnosed 1 year ago with locally advanced poorly differentiated basaloid squamous cell carcinoma of the lower anterior mandibular alveolus involving cortical, medullary bone, and perineural invasion. He underwent extensive tumor resection with reconstruction, tracheostomy, and bilateral neck dissection, followed by multiple revision surgeries for postoperative complications. He completed adjuvant chemoradiotherapy. He presented with acute confusion without other systemic symptoms. His Glasgow Coma Scale was E4V4M5. Neurological and systemic examinations were unremarkable, and oral cavity assessment showed no evidence of recurrence. Investigations revealed severe hypercalcemia (5.94 mmol/L) with normal phosphate (1.16 mmol/L) associated with shortened QTc. Other tests were unremarkable, with no evidence of infection, uremia, liver dysfunction, or alternative metabolic causes. Lumbar puncture was unremarkable. His parathyroid hormone level was suppressed at 0.50 pg/ mL. Computed tomography brain showed no evidence of meningoencephalitis, hydrocephalus, cerebral oedema, or metastasis. Aggressive hydration was initiated alongside subcutaneous calcitonin, which was subsequently titrated. However, there was no clinical or biochemical improvement after 1 day, with persistent confusion and calcium remaining at 5.87 mmol/L. Subcutaneous denosumab was then administered, and hemodialysis was initiated on alternate days due to refractory hypercalcemia. This resulted in improvement of calcium levels to 3.2–3.6 mmol/L and resolution of confusion Conclusion Refractory hypercalcemia may represent a late manifestation of advanced squamous cell carcinoma and is an ominous prognostic indicator, necessitating prompt evaluation and oncologic management.
Calcitonin ; Denosumab ; Hypercalcemia ; Renal Dialysis ; Neoplasms