The patient went on to have a biopsy of the occipital lobe.
Paraffin sections show a densely hypercellular tumour. Tumour cells have features of atypical large lymphoid cells with large round and oval vesicular nuclei many with conspicuous nucleoli and a narrow rim of pale cytoplasm. These are arranged in diffuse sheets in a vascular stroma. Frequent mitotic figures and apoptoses are identified. Tumour appears to completely replace brain parenchyma.
Atypical lymphoid cells show strong membrane staining for CD20, strong nuclear staining for bcl-6 and MUM-1 and strong perinuclear staining for bcl-2. Moderate numbers of small CD3+ T lymphocytes are scattered among the large atypical cells. No staining for CD5, CD23 or cyclin D1 is seen in the large atypical cels.
The features are of non Hodgkin lymphoma - diffuse large B cell type.
EBER-CISH is NEGATIVE
DIAGNOSIS: non Hodgkin diffuse large B cell lymphoma.