If a brainstem glioma is exophytic and enhancing, with or without cystic areas, what would the more likely histology be?
Pilocytic astrocytoma (WHO grade I).
Which phakomatosis are brainstem gliomas associated with?
Neurofibromatosis type I (NF1).
What does the presence of 'fluid intensity' regions with surrounding enhancement suggest?
Suggests that this represents a higher grade tumour than the more common WHO II diffuse astrocytomas (the usual 'brainstem glioma').
When associated with NF1 do they carry a better or worse prognosis?
MRI of the brain confirms the presence of a large mass expanding the pons. It is T1W hypointense and T2W hyperintense, with areas on the left which demonstrate fluid signal intensity and mostly attenuated on FLAIR. These areas also demonstrate peripheral irregular contrast enhancement. The mass overall does not demonstrate restricted diffusion, nor are there convincing areas of calcification or haemorrhage on gradient echo.
The fourth ventricle is effaced and hydrocephalus is present.