Brown Tumor of the Ulna and Radius: An Unusual Presentation of Primary Hyperparathyroidism

Brown tumors are erosive bony lesions caused by chronic excessive secretion of parathyroid hormone. Since the introduction of routine calcium measurement, the diagnosis of hyperparathyroidism has usually been made in asymptomatic patients and as a result, brown tumors are rarely observed as an initial manifestation of hyperparathyroidism. We report the case of a 70-year-old woman who presented with right wrist pain. A roentgenogram showed erosive bone tumors of the ulna and radius, which were mistaken for primary or metastatic bone tumors. Extensive workups were performed to determine the cause(s); however, these lesions were finally diagnosed as brown tumors associated with primary hyperparathyroidism due to a parathyroid adenoma. This case illustrates the diagnostic pitfall in patients who present with skeletal manifestations of hyperparathyroidism and the need for vigilance and a high level of suspicion by physicians. (J Korean Endocr Soc 23:347~351, 2008)