Fig. 19

Chordoma. Axial head CT (a) shows an osteolytic destructive lesion involving the clivus (thick arrows) with extension into the posterior sphenoid sinus (arrowhead) and impression on the pons (curved arrow). Axial T1-weighted (b), axial T2-weighted (c) and sagittal post-contrast T1-weighted (d) images demonstrate an expansile mass centred at the clivus extending into the sphenoid sinus (arrowhead), left cavernous region (short, thick arrows) and partially encasing the left internal carotid artery. This mass enhances and displaces the pituitary gland (thin, long arrow) and has mass effect on the left aspect of the pons (curved arrow)