CARTILAGINOUS TUMORS AND CHORDOMAS OF THE CRANIAL BASE

Chordomas and chondrosarcomas are uncommon skull base tumors that are locally aggressive. Chordomas arise from the clivus with the epicenter in the midline of the skull base. Chondrosarcomas, in contrast, usual ly arise along the petro-occipital fissure. Occasionally, a chondrosar coma may be revealed in a midline location and then cannot be differen tiated from chordoma. Chordomas rarely calcify whereas calcification i s not an uncommon finding in chondrosarcomas. The prognoses of chordom as and chondrosarcomas vary. Long-term survival is usually seen with c hondrosarcomas but is still considerably compromised with chordomas.