Benign osteoblastoma of the odontoid process of the axis with secondary aneurysmal bone cyst component: a case report

The authors report their experience on one patient with osteoblatoma of the odontoid process of the axis with secondary aneurysmal bone cyst. According to their knowledge, this is the first case, reported in the literature, of this kind of lesion in that particular anatomical region. Because of the rarity of this lesion, it was difficult to have a certain preoperative diagnosis. Therefore, the patient underwent a biopsy via a transoral route. The biopsy was performed over the noncalcified component of the lesion. The intraoperative histological examination showed the benign nature of the lesion. Thereafter, the lesion was totally removed, succeeding in preserving the remaining part of the odontoid process and the anterior arch of C1. In the follow-up, there was no evidence of cranio-vertebral instability. The histological examination revealed an osteoblastoma of the odontoid process of the axis with a secondary aneurysmal bone cyst. To the best of our knowledge, this is the first case reported in the literature.