Gangliocytoma

Case contributed by RMH Neuropathology

Presentation

Epilepsy.

Patient Data

Age: 29
Gender: Male

MRI Brain

Modality: MRI

There is a 12mm FLAIR hyperintense lesion within the right frontal white matter immediately anterior to the right lentiform nucleus. A tail of abnormal signal extends to the right lateral ventricle frontal horn. No negative mass effect or central cystic component.

A FLAIR hyperintensity mass is also demonstrated within the right mesial temporal lobe, centred in the amygdala. This predominantly involves cortex but extends into the subcortical white matter. No uncal herniation or ventricular compression.

Neither lesion demonstrates enhancement, diffusion restriction, hemosiderin staining or elevated CBV (not shown). Spectroscopy demonstrates elevated choline and decreased NAA in the right mesial temporal lobe. Incidental left frontal developmental venous anomaly.

Conclusion: The right anteromedial temporal lobe mass has features most suggestive of low grade glioma. The right frontal white matter lesion is more indeterminate and may reflect either a further focus of glioma, a developmental lesion or an incidental ischaemic/demyelinating focus.

Modality: Pathology

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)

Case Discussion

Gangliocytomas are rare benign (WHO grade I) CNS tumours which differ from gangliogliomas by the absence of neoplastic glial cells. Both tumours are defined by the presence of displaced ganglion cells (large mature neurons that show cytological or architectural abnormalities). 

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Case Information

rID: 39123
Case created: 20th Aug 2015
Last edited: 24th May 2016
Inclusion in quiz mode: Included

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