Both chordomas and chondrosarcomas are rare, slow growing tumors that can arise in the skull base. Chordomas arise from embryonic notochordal remnants along the neuraxis while chondrosarcomas derive from transformed cells that produce cartilage.  Historically, chordomas have been divided into three histopathologic subtypes: typical, chondroid and dedifferentiated. Chondroid chordomas can resemble low-grade chondrosarcoma but have a better prognosis than typical chordoma. Dedifferentiated chordomas have a more aggressive profile. Chondrosarcomas, on the other hand, are classified based on the World Health Organization (WHO) grading system (grade 1, 2 and 3).  For patients with chondrosarcoma, metastases occur in about 10 percent of cases. Patients with chordoma have a low metastases rate, but very high local recurrence rate.

Endoscopic Endonasal Surgery for Chordomas and Chondrosarcomas

Surgical Anatomy and Technical Nuances