Brown tumor of hyperparathyroidism masquerading as central giant cell granuloma in a renal transplant recipient: a case report.

The brown tumor of hyperparathyroidism is histologically identical to the central giant cell granuloma (CGCG), but these lesions can be differentiated based on history and laboratory findings. Herein we have reported a 46-year-old renal transplant recipient in whom brown tumors of hyperparathyroidism were detected several years following renal transplantation. The lesions initially masqueraded as a CGCG with an intranasal mass and ethmoid bone involvement at 7-years posttransplantation, for which surgical resection had been performed. Six years later, she developed multiple expansile bony lesions of the chest wall with histologic features of multinucleated giant cells. A markedly elevated parathyroid hormone level led us to make a diagnosis of brown tumor of hyperparathyroidism. Hence, we propose that clinicians consider brown tumor of hyperparathyroidism to be a potential cause of giant cell lesions among renal transplant recipients. Moreover, careful follow-up examinations are required for such patients to make a timely and accurate diagnosis.