Oligodendroglioma (grade 3)

Case contributed by Frank Gaillard
Diagnosis certain



Patient Data

Age: 60 years
Gender: Female

Left frontal T2/FLAIR heterogenous mass contains foci of intrinsic T1 hyperintensity and susceptibility low signal. Phase-contrast images suggest both calcification and hemorrhage within the lesion. Definite localization of the mass is difficult to delineate, however, an impression is that the mass is extra-axial at least in part with some intra-axial component. Multiple flow voids within the mass are consistent with abnormal vessels. Heterogenous enhancement of the mass with adjacent dural enhancement post-contrast. A rim of T2/FLAIR non-enhancing hyperintensity surrounding the mass. Low ADC values within the enhancing components, measuring around 680 x 10-6 mm2/s.

Associated positive mass effect on the ipsilateral lateral ventricle and adjacent brain structures, leading to subfalcine herniation to the right and 12mm midline shift rightwards. No hydrocephalus. MRA (not shown) demonstrates displacement of the anterior cerebral arteries to the right by the mass. Otherwise, no aneurysm, vascular malformation or high-grade stenosis identified. No additional intracranial enhancing lesion is seen. The remainder of the brain is unremarkable.

Conclusion: Large left frontal mass is most likely intra-axial and most likely represents a highly cellular oligodendroglioma (likely anaplastic). 


Sections show multiple fragments of glial tissue which has a cellular neoplasm. The tumor consists of round cells with round nuclei with stippled chromatin pattern. The tumor cells have a moderate amount of granular eosinophilic cytoplasm with some perinuclear clearing. There is a background delicate vascular structure with calcifications present. The figures are not conspicuous. No endovascular proliferation or necrosis is seen.   


  • Olig-2: Positive 
  • IDH-1 R132H: Positive (mutated) 
  • ATRX: Intact (non-mutated) 
  • p53: Positive (unusual in oligodendrogliomas, but reported)
  • ki67: 60% 

1p19q co-deletion confirmed by FISH. 


oligodendroglioma, IDH-mutant, and 1p/19q-codeleted (grade 3)

Case Discussion

This case illustrates the benefits of additional sequences (SWI and diffusion and perfusion) in narrowing the differential diagnosis. 

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