Skull base chordoma: CT and MRI features.

We report the case of a 10-year-old boy who presented an intracranial chordoma and we stress the importance of sectional imaging to approach the diagnosis. Clinical presentation is related to local invasion. Lesion of the body of the clivus can extend ventrally or dorsally and cause cranial nerve palsies, brain stem compression or hydrocephalus. Pathologically, they form soft, grey masses that are histologically benign but locally invasive and destructive. Both computed tomography (CT) and magnetic resonance (MR) imaging clearly depict the lesion. CT better demonstrates bone destruction and intralesional calcifications. In our case, MR was performed first and showed all the classical signs of skull base chordoma. CT provided complementary information about bone destruction which are also usual in this type of lesion. Major differential diagnoses of the chordoma in the clivus are the other central skull base masses. Biopsy and histology make the diagnosis. Usually treatment consists in surgery and radiotherapy but more recently proton beam therapy is used and seems to yield better results.