GFAP and astroblastoma: The differential diagnoses include metastatic papillary adenocarcinoma, which is epithelial membrane antigen (EMA) and cytokeratin (CK) positive but vimentin negative; papillary ependymoma, which is glial fibrillary acidic protein (GFAP) positive; astroblastoma which is characterized by a typical palisaded pattern of astrocytic cells with broad and non-tapering strongly GFAP positive processes radiating towards the central blood vessels.