MICROSCOPIC DESCRIPTION: 1. Paraffin sections show a small fragment of oedematous brain parenchyma. This contains a population of pleomorphic ganglion cells mixed with reactive astrocytes. No mitotic figures, vascular proliferation or necrosis are seen. 2. The sections show cerebral cortex and white matter. Cortex shows normal laminar architecture. No features of malformation of cortical development are seen. White matter appears of normal cellularity. Myelin is intact. No inflammation is seen and there is no evidence of tumour. 3&4. The sections of uncus and hippocampus show a prominent population of pleomorphic ganglion cells. These have a haphazard arrangement. Several binucleate forms are noted. These are admixed with a population of reactive astrocytes. No mitotic figures are identified and there is no vascular proliferation or necrosis. Immunohistochemistry shows strong nuclear staining for NeuN and strong granular cytoplasmic and membrane staining for synaptophysin in the ganglion cells. A neoplastic glial component is not demonstrated with immunohistochemistry showing GFAP reactivity in a population of reactive astrocytes, preserved nuclear immunostaining for ATRX and no staining for IDH-1 R132H or p53. Nuclear staining for topoisomerase is seen in only an occasional cell. The features are of gangliocytoma (WHO Grade I). The hippocampus shows a preserved population of neurones. There is no dispersion of dentate fascicular neurones.
DIAGNOSIS: 1,3,4: Brain tissue; Uncus; Hippocampus: Gangliocytoma (WHO Grade I) no features of hippocampal sclerosis seen. 2: Right temporal lesion: Unremarkable temporal neocortex and white matter. (MFG)