Presentation
Headache and vomiting
Patient Data
Right frontal mass, largely involving cortex with high T2 signal and no T2/FLAIR mismatch exerts significant local mass effect. No calcification or hemorrhage or solid enhancement or necrosis.
The patient went on to have tumor debulking.
Histology
Path proven oligodendroglioma, WHO grade II.
Note: IDH mutation and 1p19q co-deletion status are not provided, are now required for the diagnosis of oligodendroglioma, although this does seem likely given the age and morphology. It should therefore be denoted as oligodendroglioma not otherwise specified (NOS).
Followup
The patient was on regular MRI brain follow-up after surgical resection and radiotherapy. Subsequent follow-up revealed the development of a small enhancing nodule in the surgical bed (not shown), so recurrence was suspected.
PET showing uptake in the surgical bed in keeping with recurrence.
The patient declined to undergo another surgical resection at that time.
Three months later, the patient presented with progressively increasing headaches.
Large heterogeneously enhancing mass with central necrosis.
Case Discussion
The patient now went on to have surgery.
Histology
This is a high-grade mixed oligoastrocytoma that shows necrosis; which at the time of this case was classified as glioblastoma with oligodendroglial component, although it might have a better prognosis than standard glioblastoma.
The previous material was reviewed and it shows low-grade oligodendroglioma.
Immunohistochemistry:
GFAP+, P53+ strongly, KI-67 high (over 25%)
Final diagnosis: Glioblastoma with oligodendroglial component, WHO grade IV.
Note: Under the current (2016) WHO classification of CNS tumors, this tumor is not easily classified. If the original tumor was indeed an oligodendroglioma (IDH mutant, 1p19q co-deleted) then this is now an anaplastic oligodendroglioma and not a glioblastoma.
As molecular status is unavailable this is best thought of as an oligodendroglioma NOS progressing to an oligodendroglioma NOS grade 3.
It may, however, have been an astrocytoma or even a glioblastoma based on the 2021 WHO classification.
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