Choroid plexus papilloma

Q: In this case, what entities should be considered? show answer

A: Ependymoma, choroid plexus papilloma, pilocytic astrocytoma, haemangioblastoma and possibly medulloblastoma.

Q: Which is most likely? What is the one atypical feature for this entity? show answer

A: The mass has appearances most in keeping with a choroid plexus papilloma: a very vividly enhancing lobulated mass within the ventricle with associated hydrocephalus. Slightly atypical is the location; unlike most paediatric brain tumours, in children choroid plexus papillomas are more frequently found in the trigone of the lateral ventricles.

Q: What features are good for haemangioblastoma? What is against the diagnosis? show answer

A: The location, vivid enhancement, flow voids and associated cystic component are all seen in haemangioblastomas. The age is atypical. Peak incidence is around 30 - 60 years of age, but earlier in patients with von Hippel Lindau (vHL) - in which case they are usually multiple.

Q: What about ependymoma? show answer

A: Although the age group and location are good, ependymomas tend to be less 'frond-like' and enhancement, although prominent, less vivid and homogeneous than choroid plexus papillomas. Ependymomas often have associated oedema in the adjacent brain; in this case there is only a little next to the cystic component superiorly on the left.

Q: What is the peak incidence of choroid plexus papillomas? show answer

A: Approximately 85% of all choroid plexus papillomas occur in children under the age of 5 years.

Q: True or false: hydrocephalus is a common feature of choroid plexus papillomas? When present, what is the believed mechanism? show answer

A: Significant hydrocephalus is very common - it is seen in over 80% of cases. Although the exact mechanism remains uncertain, it is believed to be due to a combination of CSF over production and decreased arachnoid granulation resorption.