Brown tumour of hyperparathyroidism in the mandible associated with atypical parathyroid adenoma

The brown tumour of hyperparathyroidism is a localized bone tumour and an u ncommon manifestation of hyperparathyroidism. A 27-year-old woman presented with a mandibular 8 x 10 cm solid mass diagnosed as central giant cell gra nuloma. Chemical blood analysis revealed increased serum calcium levels of 12.16 mg/dL and the parathyroid hormone level was 124 pg/dL. The patient un derwent surgery with removal of a parathyroid mass. Histologically, this pa rathyroid tissue was seen to be limited by a fibrous capsule with morpholog ical features consistent with atypical parathyroid adenoma. The mandibular tumour has receded and the patient declined further procedures. This is the first case reported of brown tumour as the primary manifestation of an aty pical parathyroid adenoma, a lesion that shares some features with parathyr oid carcinoma without the unequivocal properties of malignancy.