Abstract Choroid plexus papillomas are rare tumours which may arise from the plexus lying in any part of the ventricular system including its lateral extension into the cerebello-pontine angles. This paper, which assesses the contribution of radiology to the diagnosis and reviews the clinical and pathological features, is based on those papillomas seen at The National Hospital since 1945. In two patients with a long history of epilepsy there was a pattern of calcification, seen on the straight skull radiographs, which is believed to be characteristic of a choroid plexus papilloma lying in the temporal horn. Fourth ventricle papillomas, on account of their early obstruction to cerebrospinal fluid pathways, present with symptoms of hydrocephalus. The favourable prognosis of surgical removal emphasises the importance of accurately outlining the 4th ventricle at ventriculography if there is dilatation of the 3rd and lateral ventricles. Cerebello-pontine angle papillomas can usually be differentiated clinicall...