[Ossifying fibroma of the temporal bone].

A case of ossifying fibroma of the cranial vault is described. Several reports emphasized the rare existence of this lesion limiting in the cranial vault. The patient was a 76-year-old woman who suffered mild headache in the parietal region after a trivial head trauma. Physical and neurological examination were normal. Plain skull X-P revealed irregularly bordered, 4 X 4 cm sized radiolucent area in the left temporal bone. The bone scintigraphy using 99mTc-MDP showed an abnormal uptake like a doughnut. Levels of serum P, Ca and alkaline phosphatase were within normal range. A tumor was softer than normal skull, and undertaken piecemeal removal. The dura was normal. After the total removal of the tumor, cranioplasty using Resin plate was performed. Microscopically the lesion was composed immature, irregular spicules of bone and fibrous tissue. Abundant fibroblasts were arranged in a random fashion in the stroma. Characteristically, the spicules of bone surrounded by rimming of osteoblasts. Ossifying fibroma is a benign fibroosseous tumor. Although this tumor is typically found in the maxillary sinus and mandible, it has also been reported in the paranasal sinuses, frontal, ethmoid, sphenoid bone and orbital roof of the young adult. But previously reported cases involving the cranial vault alone were only 7 cases. Etiology of ossifying fibroma is almost unknown.