[CT findings in chordomas of the base of the skull].

Nine chordomas of the skull base and their CT appearances are described. Destruction of the clivus and of the parasellar portions of the middle fossa are characteristic, as is calcification which may be spotty, coarse or ill-defined. The tumour is characterised by marked enhancement following contrast but, on the unenhanced CT, contrary to statements in the literature, it is hypodense or isodense with respect to cerebral tissue. The tendency to recurrence and an altogether poor prognosis is confirmed.