Tooth mobility revealing a brown tumor associated with normocalcemic tertiary hyperparathyroidism: case report and literature review

Abstract Background Brown tumors are rare non neoplastic lesions resulting from abnormal bone metabolism in hyperparathyroidism. They are rarely observed in tertiary hyperparathyroidism. Tertiary hyperparathyroidism is a very rare condition that arises in the setting of renal disease. It is the autonomous secretion of parathyroid hormone leading to persistent hypercalcemia and elevated serum parathormone despite resolution of the underlying problem. Case presentation: we report an unusual case of tooth mobility revealing the presence of a brown tumor located in the mandible in a north African 41 year old male with chronic kidney disease and a history of parathyroidectomy. Clinical examination revealed firm vestibular swelling. Radiographic assessment showed a well-defined periapical radiolucent lesion, consistent with a giant cell lesion. Elevated parathyroid hormone levels (3283.0 pg/ml), normocalcemia, and hyperphosphatemia supported the diagnosis of a brown tumor due to tertiary hyperparathyroidism. The treatment of brown tumor consists of addressing the underlying hyperparathyroidism. The unusual observation is that the patient presented with elevated parathormone level associated with normocalcemia raising the question on the indication for parathyroidectomy in this case. Conclusion The patient initially benefited from a parathyroidectomy with a reduction in serum parathormone by over 50% and tumor regression. However, 2 months later, we observed a recurrence of parathormone levels ,while calcium levels remained normal, necessitating the use of high dose calcimemitic agents. This case highlights the importance of thorough evaluation in patients with chronic kidney disease and persistent hyperparathyroidism, and also the question of the indication of parathyroidectomy in normocalcemic tertiary hyperparathyroidism