Anaplastic oligodendroglioma NOS

Case contributed by Dr Hani Salam


Headache and vomiting

Patient Data

Age: 30 years
Gender: Male

Right frontal mass, largely involving cortex. 

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. 

The patient was on regular MRI brain follow-up after surgical resection and radiotherapy. Subsequent follow-up reveals the development of a small enhancing nodule in the surgical bed (not shown), so recurrence was suspected. PET brain confirmed the presence of high metabolic rate lesion correlating to the MRI finding.

However, the patient refused to undergo another surgical resection. 

Three months later, the patient presented with progressively increasing headache. 

Nuclear medicine

PET showing uptake in the surgical bed in keeping with recurrence. 


MRI brain follow-up

Large heterogeneously enhancing mass with central necrosis. 

Case Discussion

The patient went on to have surgery. 


This is a high-grade mixed oligoastrocytoma that shows necrosis; which should be 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.

GFAP+, P53+ strongly, KI-67 high (over 25%)

Final diagnosis:  Glioblastoma with oligodendroglial component, WHO grade IV.

NoteUnder 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 anaplastic oligodendroglioma NOS.

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Case information

rID: 10699
Published: 7th Sep 2010
Last edited: 17th Oct 2019
Inclusion in quiz mode: Included

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