The patient went on to have surgery and resection of the mass. 


MICROSCOPIC DESCRIPTION: Sections  show  fragments of  tumour,  comprising  uniform, rounded nuclei within a delicate  fibrillary neuropil-like  stroma.  There are cell free neuropil-like islands,  and delicate branching  capillaries within the stroma.  Mitotic figures are not  observed within tumour cells.  The tumour shows strong diffuse  staining for synaptophysin  and NeuN, and is negative for GFAP,  which  stains  background  astrocytic  processes.    There is no microvascular proliferation.   Necrosis is observed,  however, particularly in association with areas  of haematoma formation  within the tumour.  ki67 within tumour cell  nuclei is interpreted  as being low,  with hot spots of staining  in  areas of  necrosis  that  may  relate  to  inflammatory  cell infiltration.

FINAL DIAGNOSIS: Intraventricular tumour - central neurocytoma, WHO Grade 2.