Patient Data
A peripherally enhancing lesion in the left frontal lobe is present with elevated CBV in the enhancing components. Central non-enhancement suggests necrosis.
The patient went on to have a craniotomy and excision.
Histology
Microscopic Description: Sections show a glioma composed predominantly of gemistocytic and micro-gemistocytic tumor cells. Oligodendroglial elements are focally seen. Focal endothelial cell proliferation is noted, and a localized area of recent necrosis is identified. Occasional mitoses are seen.
Final Diagnosis: glioblastoma
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 glioblastoma NOS.
Note: The diagnosis of glioblastoma is actually not entirely established in this case as the IDH wild-type status has not been assessed. Although in this age group it is likely to reflect an IDH wild-type glioblastoma, it is possible that this is an IDH mutant glioblastoma (secondary glioblastoma). If an IDH mutation were to be found, then 1p19q codeletion status would also need to be established
This is important from a classification and prognosis point of view as if an IDH mutation was found and 1p19q was co-deleted then this tumor would actually represent an anaplastic oligodendroglioma and not a glioblastoma.
Case Discussion
The presence of necrosis and endothelial proliferation is consistent with a WHO grade IV tumor.