Hypercalcemia of malignancy is a common paraneoplastic syndrome among patients with renal cell carcinoma (RCC), affecting up to 20% of patients. We report a case of metastatic RCC in a man presenting with severe hypercalcemia. A 76-year-old gentleman presented with 2 weeks of lethargy and dyspnea. He had a 50 pack-year smoking history. Examination revealed diminished breath sounds. Abdomen was soft with mild left flank tenderness. Blood tests revealed severe hypercalcemia (corrected calcium 4.09 mmol/L, range: 2.10-2.60 mmol/L), with a concurrent suppressed parathyroid hormone (PTH) level (0.5 pmol/L, range: 1.3-7.6 pmol/L), consistent with non-PTH mediated hypercalcemia. Chest X-ray showed bilateral pleural effusions with nodular opacities. A CT demonstrated an 8cm mass arising from the superior pole of the left kidney suspicious for a renal cell carcinoma, with innumerable pulmonary nodules, large bilateral pleural effusions, as well as mediastinal, hilar and para-aortic lymphadenopathy. Iatrogenic hypercalcemia and multiple myeloma were excluded. 1,25-dihydroxyvitamin D level was normal. Measurement of parathyroid hormone-related peptide was not feasible. Following treatment with intravenous fluid and zoledronic acid, his calcium level normalized twelve days later. He underwent a therapeutic and diagnostic thoracentesis. His radiological findings and pleural fluid cytology result were in keeping with metastatic renal cell carcinoma. He was commenced on pazopanib. He required bilateral long-term indwelling pleural catheter insertion for recurrent bilateral pleural effusions. He was discharged home after 4 weeks of hospitalization but was readmitted to hospital 6 weeks later with worsening dyspnea. CT showed progression of pulmonary metastases. He died 12 weeks after his initial presentation. RCC has protean manifestations and hypercalcemia is the most common paraneoplastic complication of RCC.
Read full abstract