GENERAL HISTOLOGY

Detailed explanation-1: -A brown tumor is a benign fibrotic, erosive bony lesion caused by localized, rapid osteoclastic turnover, resulting from hyperparathyroidism. Although brown tumors are one of the most pathognomonic signs of primary hyperparathyroidism, they are rarely seen in clinical practice.

Detailed explanation-2: -Clinically, brown tumors present as painful, hard, clearly visible and palpable swelling. Radiographically, they appear as well-demarcated monolocular or multilocular osteolytic lesions, with root resorption and loss of the lamina dura seen occasionally.

Detailed explanation-3: -Brown tumors are giant cell lesions caused by abnormal bone metabolism in hyperparathyroidism. Increased circulating PTH aggravates osteoclastic bone absorption, then leads to diffuse osteopenia, fractures or multiple circumscribed lytic lesions [7, 8].