In a 30 year old the differential for a posterior fossa haemorrhagic mass is mainly between a haemangioblastoma and an ependymoma, although haemorrhage in both is quite uncommon. Pilocytic astrocytomas can rarely haemorrhage as can medulloblastomas, however in both cases the age group is a little atypical. Metastases would be unusual in a patient of this age.
The sections show multiple fragments of variably but up to moderately cellular tumour. Part of the tumour has an ependymal lining but the tumour has a distinctive pattern of moderately pleomorphic oval nuclei with speckled chromatin in a neurofibrillary background. Perivascular pseudorosetting is a prominent feature. In areas, true rosettes with lumens are also noted. Areas of tumour necrosis are not seen but there are focal collections of hemosiderin-laden macrophages and focal fibrosis is noted. An occasional mitotic figure is noted. The features are those of a classical ependymoma.
DIAGNOSIS : Posterior fossa tumour - ependymoma, WHO grade 2.