Ossifying cementicular fibroma of the orbitofrontal bone in a child: case report.

A rare case of ossifying cementicular fibroma of the left orbitofrontal bone that developed in a 12-year-old boy is presented. A hard, painless mass that was incidentally noticed gradually enlarged over 2 years. Skull X-rays showed a well-demarcated lesion with mixed sclerotic and osteolytic radiolucent changes in the left orbitofrontal bone. Computed tomography revealed an expansile intradiploic multilocular mass that was separated by bony trabeculae. T1-weighted magnetic resonance imaging demonstrated a multi-cystic iso-intense mass with homogeneous contrast enhancement. Left external carotid angiograms revealed a vague tumor stain that was mainly fed by the middle meningeal artery. Systemic bone scintigrams revealed a single abnormal uptake in the lesion. The skull tumor was totally removed. Histological examination demonstrated two different characteristic findings that were composed of fibrous dysplasia and cementifying fibroma, although most of the tumor appeared to be a highly cementicular form of fibro-osseous lesion. The pathological diagnosis was a cementicular variant of fibrous dysplasia.