Primary Hyperparathyroidism With Brown Tumor of the Mandible Misdiagnosed as a Giant Cell Tumor: A Case Report.

In this case study, we present an incidentally discovered giant cell granuloma, which, upon detailed investigation, led to an unexpected diagnosis. A 36-year-old woman exhibited a bone lesion in the right retromolar trigone area, initially suspected of being malignant. However, histopathological examination revealed a giant cell tumor of bone. Further biochemical profiling, including serum calcium, phosphorus, and parathyroid hormone (PTH) levels, showed elevated PTH and hypercalcemia, prompting consideration of primary hyperparathyroidism and the diagnosis of a brown tumor due to this condition. This case underscores the importance of considering brown tumors associated with primary hyperparathyroidism as a potential differential diagnosis in patients with lytic bone lesions.