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 fronto-parietal osteoblastoma accompanying a secondary aneurysmal bone cyst.


METHODS
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.


CONCLUSIONS
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.
Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8677, Japan. kubota-cbu@umin.ac.jp
Yoshitaka
Y
Kubota
Nobuyuki
N
Mitsukawa
Risa
R
Arikawa
Shinsuke
S
Akita
Kaneshige
K
Satoh
D001707:Biopsy, Needle; D017824:Bone Cysts, Aneurysmal / Q000150:complications / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D001859:Bone Neoplasms / Q000150:complications / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D003399:Craniotomy / Q000379:methods; D005500:Follow-Up Studies; D005624:Frontal Bone; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009367:Neoplasm Staging; D019635:Neurosurgical Procedures / Q000379:methods; D018215:Osteoblastoma / Q000150:complications / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D010294:Parietal Bone; D018570:Risk Assessment; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult