MACROSCOPIC DESCRIPTION: Two fragments of soft gelatinous tissue up to 3mm.
MICROSCOPIC DESCRIPTION: Paraffin section shows small feragments of moderately hypercellular tissue. These are composed of cells with uniform small round nuclei with an open chromatin arrangement and delicate processes. These are arranged in columns consistent with glioneuronal elements. Spaces filled with mucinous material are noted throughout the tissue fragments. An occasional mature neuron is identified (NeurN stain). No mitotic figures are identified and there is no vascular endothelial cell hyperplasia and no necrosis. Immunohistochemistry shows strong staining for synaptobrevin in the small cells. The features are of dysembryoplastic neuroepithelial tumour (DNET). The topoisomerase labelling index is <1%.
DIAGNOSIS: Dysembryoplastic neuroepithelial tumour (DNET) WHO Grade I