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.