Hypercalcemia in Dual Pathology: Interplay Between Renal Cell Carcinoma and Parathyroid Adenoma

The concomitant occurrence of renal cell carcinoma (RCC) and primary hyperparathyroidism is rare as these conditions are often identified by the presence of hypercalcemia, which might be missed in asymptomatic individuals. We present the case of a 58-year-old asymptomatic male detected to have a left abdominal mass during his routine medical follow-up. He was subsequently diagnosed with RCC. Further history revealed that his calcium levels had been persistently elevated for the past eight years but had never been investigated. Based on elevated parathyroid hormone levels and radiological findings, a diagnosis of primary hyperparathyroidism has also been made. A right inferior parathyroidectomy was performed, and the histopathological examination results showed a right parathyroid adenoma. Intraoperative intact PTH (iPTH) measurements confirmed the complete removal of the abnormal parathyroid gland. The postoperative calcium levels have returned to normal. To the best of our knowledge, this was the first reported case of concurrent primary hyperparathyroidism and RCC in our population. This case illustrates the importance of considering a broad differential when evaluating patients with hypercalcemia.