Brown Tumors Mimicking Skeletal Metastases: A Diagnostic Pitfall in Primary Hyperparathyroidism.

Brown tumors are rare but important manifestations of primary hyperparathyroidism (PHPT). These benign, fibrotic, and erosive bony lesions result from localized rapid osteoclastic activity driven by excessive parathyroid hormone levels. Although brown tumors are considered one of the most pathognomonic signs of PHPT, they are infrequently encountered in clinical practice. They closely mimic malignant osteolytic processes, posing a diagnostic challenge, especially in cases of undiagnosed hyperparathyroidism. Radiographic findings often resemble those of metastatic bone disease or primary bone malignancies.