MICROSCOPIC DESCRIPTION: Paraffin sections show fragments of a moderately hypercellular  tumour composed of cells with uniform round and oval nuclei with  finely granular chromatin and delicate processes. These are arranged  in diffuse sheets and perivascular pseudo-rosettes. No mitotic figures  are seen and there is no vascular endothelial cell hyperplasia and no  necrosis. Myxoid-mucinous material is noted in some of the pseudo-rosettes interposed between the central blood vessel and the  surrounding corona of tumour cells. Tumour cells show strong  immunostaining for GFAP. Weak staining for epithelial membrane antigen  (EMA) is noted in some pseudo-rosettes. The features are of  myxopapillary ependymoma. The Ki-67/MIB-1 labelling index is <1%.  4. The section shows a dense collagenous membrane covered on one  surface by tumour with features as described in specimens 1-3. No  nerve tissue is identified.   

FINAL DIAGNOSIS: Myxopapillary ependymoma.(WHO Grade I)