SEER Inquiry System - Question 20021152 Details

Default the coding of the Primary Site field for chordomas to the bone where the tumor began in the body if the primary site is not clearly stated to be soft tissue. Bone is often the primary site for chordomas.

Based on advice from pathologist consultants: This is one of those situations where we can be quite comfortable with a default, in this case to bone, not soft tissue. Chordoma is a tumor arising in the nucleus pulposis, presumably from remnants of notochord - thus its exclusive origin is in the sacrococcygeal region, spheno-occipital region, and vertebral bodies, otherwise known collectively as the axial skeleton. Any "chordoma" in soft tissue (with no relationship to axial skeleton) is probably a myxoid chondrosarcoma or parachordoma (extremely rare).