[A giant chondromyxoid fibroma originated from the right orbital roof.--A case report--].

The authors reported a case of giant chondromyxoid fibroma of the right anterior cranial fossa, arising from the right orbital lamina of frontal bone. A fifteen-year-old boy was admitted because of a recent history of the right exophthalmus and headache. Neurological examination was essentially negative except papilledema in the both optic fundi and the right olfactory disturbance. Skull plain x-ray films showed the bony destruction of the right supraorbital bone and the some of abnormal calcification in the right anterior cranial fossa. CT scan showed cystic low density spots surrounded by irregular ring-like high density areas in the right anterior cranial fossa. Operation was performed on two stages and the tumor was removed totally. The tumor was arising from the orbital lamina of the frontal bone. The size of resected tumor was 7x5x4 cm. The pathological examination confirmed the diagnosis of chondromyxoid fibroma. Postoperatively, the patient is fully schooling without any disturbance 2 years and 7 months after the discharge. In Japan, two cases of intracranial chondromyxoid fibroma have been reported in literature. The authors discussed the histology of chondromyxoid fibroma and the genesis of the membraneous bone origin of the intracranial chondromatous tumor.