Abstract
BACKGROUND: Parathyroid cancer is a rare cause of primary hyperparathyroidism. It presents a diagnostic and therapeutic challenge that may not be recognized preoperatively, and is often not conclusively identified during the operation. We present the case of a lady with backache and hypercalcemia, but with inadequate work-up for her condition for several years. CASE PRESENTATION: A middle aged lady of Asian descent presented with backache. Initial work up revealed mild hypercalcemia, negative work up for multiple myeloma, negative sestamibi scan for parathyroid pathology. A phenomenally elevated parathormone (PTH) level-2105 pg/mL (16-87 pg/mL), and rising serum calcium, 15.1 mg/dL, (8.6-10.5 mg/dL), ordered years later prompted a repeat sestamibi scan and ultrasonography of neck. Based on these investigations, a diagnosis of primary hyperparathyroidism, with high suspicion of parathyroid cancer was made. The patient underwent surgical tumour resection, with subsequent histopathological confirmation of diagnosis. CONCLUSION: In the setting of hypercalcemia, PTH level assessment is a must. This helps to differentiate between the parathyroid dependant and independent causes of high serum calcium, thereby encouraging a comprehensive pathway to the work up of the cause of hypercalcemia. The parathyroid cancer is a very rare cause of hypercalcemia, which needs to be considered in the differentials of primary hyperparathyroidism, particularly in the setting of high PTH levels.