Lobulated extra-axial mass centred on the pre-pontine and pre-medullary cisterns. The mass is hyperdense with a punctate focus of internal calcification posterosuperiorly. There is compression on the adjacent brainstem and the fourth ventricle, better appreciated on recent MRI, with bilateral temporal horn dilatation which is unchanged. There is evidence of associated clival erosion with destruction of cortical bone predominantly to the right of the midline. Mild periventricular white matter and left frontal hypodensity are unchanged. No further abnormality is seen.