Summary

Brown tumour is a rare focal giant-cell lesion that arises as a direct result of the effect of parathyroid hormone on bone tissue in patients with hyperparathyroidism (HPT). The lesions localise in areas of intense bone resorption, and the bone defect becomes filled with fibroblastic tissue. It can affect the mandible, maxilla, clavicle, ribs and pelvic bones. Therefore, diagnosis requires a systemic investigation for lesion differentiation. The authors present a case of a 27-year-old woman, with a rare case of brown tumour of mandible due to HPT secondary to osteomalacia. The lesion showed a tendency to recur even after excision till her parathyroid levels became normal.