Seven Year-follow-up of a Brown Tumor in the Maxilla Associated with Secondary Hyperparathyroidism in End-stage Renal Failure

Abstract

Hyperparathyroidism is a frequent complication of chronic kidney disease (CKD) as a result of prolonged hyperphosphatemia and hypocalcemia. Brown tumor is a rare bony complication of hyperparathyroidism as a result of increased osteoclastic activity and fibroblastic proliferation. Frequent sites of brown tumor are known as ribs, clavicles, mandible, and pelvic bone, but maxilla is very rare site. Twenty seven-year-old woman with stage V CKD on hemodialysis presented with maxillary mass which had gradually increased in size for 3 years. It was painless, but tooth derangement occurred. Initial laboratory findings revealed hypercalcemia (11.0 mg/dL), hyperphosphatemia (6.9 mg/dL), high creatinine (7.5 mg/dL), and high serum PTH (1729.9 pg/mL). The bone mineral density was significantly low (lumbar spine Z-score: -4.1, femur neck Z-score: -4.5). Radiologically, there were resorptive lesions in the maxilla. We performed total parathyroidectomy with transplanting half of her parathyroid gland on her right forearm. After surgery, serum PTH was markedly decreased to normal level. Immediate post-operative hypocalcemia developed without any change in serum Pi, then calcium gradually normalized. Seven years after the parathyroid surgery, she finally underwent renal transplantation that lead her calcium, phosphate and creatinine corrected to normal range, and the size of brown tumor has decreased further more. We report a case of long term follow up on a brown tumor in the maxilla which is infrequent site finally recovered.