[Hydrocephalus and brainstem tumor of late manifestation].

We report two clinico-pathological cases with an initially hidden brainstem tumour presenting as chronic hydrocephalus of "idiopathic type". Diagnosis was established respectively one and two years after a successful shunting procedure, as repeated CT scan was performed because of gait deterioration. The first case was a bifocal glioblastoma invading the leptomeninges of the posterior fossa and spinal cord, and resulting in a communicating hydrocephalus. The second case was an ependymoma of the fourth ventricle leading to e non-communicating hydrocephalus. Rarity of such cases is emphasized.