Clival chordomas.

Three cases of clival chordomas are reviewed and the findings are compared to those in the recent literature. In the first case the tumour arose from the basion, spreading downwards to invade the upper cervical canal and the paravertebral fascial planes. The second case is a rare case since it affects a 12 year old pre-adolescent boy. The third case showed the characteristic features of petro-clival erosion and a large extracranial component in the nasopharynx. In all three cases, computed tomography was an excellent modality for demonstrating bone destruction, sequestra and calcification but inferior to magnetic resonance imaging (MRI) in demonstrating the soft tissue extent of the tumour. The multiplanar capability of MRI was found to be particularly useful for planning treatment. Vertebral angiography can demonstrate the tumours by vessel displacement, encasement and vascular staining. Two cases had angiography and demonstrated tumour blush. Pre-operative embolization was helpful in one case.