Ependymoma (hemorrhagic)
In a 30 year old the differential for a posterior fossa hemorrhagic mass is mainly between a hemangioblastoma and an ependymoma, although hemorrhage in both is quite uncommon. Pilocytic astrocytomas can rarely hemorrhage as can medulloblastomas, however in both cases the age group is a little atypical. Metastases would be unusual in a patient of this age.
Pathology
The sections show multiple fragments of variably but up to moderately cellular tumor. Part of the tumor has an ependymal lining but the tumor 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 tumor 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 tumor - ependymoma, WHO grade 2.