Hyperparathyroidism leads to the development of a brown tumour in 2-3% of cases, which can manifest anywhere in the skeleton. Increased parathyroid hormone results in increased osteoclast activation and increased calcium and phosphate. Bone resorption outweighs new bone formation. As a result, giant cell-containing tissue forms, replacing physiologic bone structure and forming radiologically detectable osteolysis.
In the present case report, a 65-year-old female patient presented with a hard, nondisplaceable, mildly pressure-dolent swelling in region 32-44. CT scan revealed a diffuse osteolytic sclerotic process extending to the mandibular base. The diagnosis was confirmed by bone biopsy. Histologically typical are multinucleated giant cells, spindle cells and haemorrhage foci organized by the release of hemosiderin, hence the name "brown tumours". Differential diagnosis includes other giant cell-containing lesions such as: central giant cell granuloma or aneurysmal bone cyst. Therefore, additional laboratory parameters must be used to establish the diagnosis. The cause of primary hyperparathyroidism, as in the described case report, is a parathyroid adenoma in 80% of cases.
The therapy consisted of the removal of the parathyroid gland. This also resulted in regression of the bony lesion, so that it did not require further surgical treatment.