Fronto-parietal osteoblastoma with secondary aneurysmal bone cyst: A case report

Background: Osteoblastomas and aneurysmal bone cysts each comprise 1% of primary bone tumours. As both osteoblastomas and aneurysmal bone cysts are not common, osteoblastomas with secondary aneurysmal bone cysts of calvaria are extremely rare. Only three cases describing a secondary aneurysmal bone cyst in the setting of a calvarial osteoblastoma can be found in the literature. We report the case of the surgical resection of the frontoparietal osteoblastoma accompanying a secondary aneurysmal bone cyst. Case description: The case is a 24-year-old male with a 2-year history of a painless lump in the hair-bearing region of the left fronto-parietal area without neurologic symptoms. Computed tomography showed an intradiploic tumour with maintained inner and outer cortex of the left front-parietal bones. 3.0-T magnetic resonance imaging showed a well-circumscribed, intradiploic, multilocular cystic tumour. A gadolinium-enhanced sequence showed strong peripheral and septal enhancement. These findings were consistent with an osteoblastoma associated with secondary aneurysmal bone cyst. An en bloc tumour resection with a 10-mm horizontal margin was completed without complications. The calvarial defect was covered by calvarial bone graft harvested from the contralateral fronto-parietal bone. The postoperative course was uneventful. Pathological diagnosis was consistent with the osteoblastoma with secondary aneurysmal bone cyst. After a follow-up period of 2 years, there was no evidence of recurrence. Conclusion: The combination of osteoblastoma and aneurysmal bone cyst of the calvaria is a rare clinical entity. Careful preoperative examination and complete resection of the tumour are essential. (C) 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.