[Intra-and extracranial chondrosarcoma]

A 17-year-old female, who had diplopia and progressive gait disturbance, had been diagnosed as having a right parasellar mass lesion in 1986. Initial CT scan failed to show a parasellar space occupying lesion, although it was well demonstrated on MRI. No surgery was carried out at that time. Seven years later, she was hospitalized because of progressive gait disturbance, lower cranial nerves palsy, and cerebellar sign as well as the known right abducence palsy. At this time, CT scan exhibited a huge low density area with a marginal high density area suggesting calcification, which extended from the right parasellar area to the ventral portion of the midbrain. She underwent surgery under the diagnosis of cartilaginous tumor or chordoma. The intracranial lesion was removed via combined translabyrinthine approach and epidural subtemporal approach. The tumor was hitologically diagnosed as well-differentiated chondrosarcoma. Electron-microscopy demonstrated tumor cells with features of chondrocytes. Since the original site of the tumor, strategies for treatment and prognosis are different from each other, distinction between chondrosarcoma and chordoma is important. MRI seemed very useful for making this distinction as a first step.