Chordoma commonly involves -a) Dorsal spineb) Clivusc) Lumbar spined) Sacrume) Cervical spine
Chordoma 

Chordoma is rare malignant tumor originating from the remanants ofprimitive notochord.
As the vertebrae develop, notochord disappears and in adults, the normal remnant of notochord is nucleus pulsosus of the intervertebral disc. In chordoma, this embryonic notochordal foci remains inside the vertebral body and forms tumors.
It occurs in adult males after 50 years.
It commonly occurs in the sacrococcygeal or in the spheno-occipital regions. Sacrum is the most common site : - Sacrum 50% clivus (35%), cervical thoracic/lumbar (15%).
Most of them occur in vertebral bodies.
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