Presentation
Seizure
Patient Data
A large area of low attenuation, mostly confined to the white matter, is seen involving the right frontal lobe. Within it is embedded a relatively ill-defined area of hyperdensity with contrast enhancement.
Hyperdensity implies high cellularity.
Differential includes high grade glioma, cellular metastasis or central nervous system lymphoma.
There are multiple intra-axial heterogeneously enhancing lesions the right cerebellar hemisphere:
- Right inferior frontal gyrus opercular region. This lesion extends to involve the cortex and possibly the leptomeninges. Increased CBV.
- Right thalamic hemorrhagic lesion protruding into the body of the right lateral ventricle, with predominantly acute stage blood product.
- Right frontal deep white matter extending into the body of the corpus callosum. MRS- inc Cho. Increased CBV. Shows low ADC values suggesting high cellularity.
Moderately extensive confluent white matter bright FLAIR/T2 signal around these lesions, with 1 cm midline shift of the septum pellucidum to the left. Right uncal herniation with right cerebral peduncle compression.
Case Discussion
This is an interesting case, in that the contrast appearance and homogeneity of the largest periventricular mass are quite good for CNS lymphoma, especially in the presence of low ADC values and high density on non-contrast CT, which implies high cellularity.
The presence of thalamic hemorrhage would be unusual for lymphoma, however (unless immunocompromised). The differential is therefore essentially between a high-grade glioma (GBM) or lymphoma. The location and appearance would be unusual for metastases. The high cellularity essentially excludes demyelination.
The patient went on to have a craniotomy.
Histology
MICROSCOPIC DESCRIPTION: The sections show features of a densely cellular astrocytic tumor. The tumor cells show elongated, angulated and hyperchromatic nuclei. Scattered large multinucleated tumor giant cells are noted. In some areas, the tumor cells have high N/C ratio with granular chromatin and nuclear molding. They show patchy positivity for synaptophysin, consistent with PNET-like differentiation. Tumor cells are seen to extend into the cerebral cortex. Scattered mitotic figures are identified. There are foci of endothelial cell hyperplasia. Some of the blood vessels show perivascular lymphocytes. Areas of necrosis are present, some with pseudopalisading. The features are those of glioblastoma.
FINAL DIAGNOSIS: Glioblastoma (WHO Grade IV).
Note: This case predates the recent (2016) revision WHO classification of CNS tumors and IDH status is not available. As such, this tumor would now be classified as a glioblastoma NOS.
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