Refractory paraneoplastic hypercalcaemia responding to cinacalcet.

Area of Science:

• Oncology
• Endocrinology
• Nephrology

Background:

• Bladder cancer is a significant health concern, often presenting with urinary symptoms.
• Hypercalcemia, a common complication of malignancy, can be paraneoplastic.
• Paraneoplastic hypercalcemia in bladder cancer is exceptionally rare.

Observation:

• An elderly female patient with advanced bladder cancer and bilateral hydronephrosis presented with hypercalcemia.
• The hypercalcemia was determined to be paraneoplastic, likely due to elevated parathyroid hormone-related peptide, without bone metastases.
• Histology revealed squamous and sarcomatoid differentiation of the bladder tumor.

Findings:

• Initial management with fluids and zolendronate provided temporary relief for hypercalcemia.
• Recurrent hypercalcemia was refractory to repeat zolendronate and denosumab treatments.
• Cinacalcet demonstrated a successful response in managing the refractory hypercalcemia, marking a novel therapeutic approach.

Implications:

• This case highlights cinacalcet as a potential treatment for refractory paraneoplastic hypercalcemia in bladder cancer.
• Further research is warranted to explore the efficacy and safety of cinacalcet in similar oncological emergencies.
• Understanding paraneoplastic syndromes associated with bladder cancer is crucial for comprehensive patient management.