Presentation
No presenting history available.
Patient Data
MRI of the brain demonstrates extensive abnormality involving the brainstem and thalami characterized by high T2 signal and positive mass effect. There is faint contrast enhancement and restricted diffusion.
The pons is markedly expanded trapping the basilar artery between the clivus and the anterior surface of the pons.
MRS demonstrates elevation of choline, elevation of the choline to creatine ratio and depression of NAA, consistent with a glioma.
Features are quite characteristic of a diffuse glioma (both brainstem glioma and thalamic glioma).
Case Discussion
The patient went on to have a biopsy.
Histology
The section shows cores of a moderately hypercellular astrocytic glioma. Tumor cells are fibrillary in type with round and elongated nuclei and bipolar processes and are arranged in loose fasciculi. No mitotic figures are seen and there is no vascular endothelial cell hyperplasia and no necrosis. Foci of microcalcification are also noted. Tumor cells show strong immunostaining for GFAP and nestin. The topoisomerase labeling index is approximately 1%.
FINAL DIAGNOSIS: Diffuse astrocytoma (WHO Grade II).
Note: It would be important to test for histone mutations (H3 K27M) as it is likely that this represents a diffuse midline glioma H3 K27M–mutant. Unfortunately, this case is historical this molecular data is not available.
Note: IDH mutation status is not provided in this case and according to the current (2016) WHO classification of CNS tumors, this tumor would, therefore, be designated as a diffuse astrocytoma NOS.
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