Definition
- Essential:
- Methylation profile of DGONC AND
- Nuclear clusters of small to medium-sized cells exhibiting oligodendroglioma-like morphology AND
- Strong expression of both OLIG2 and synaptophysin AND
- Absence of widespread GFAP expression
- Desirable:
- Monosomy of chromosome 14
- Caveat:
- DNA methylation profiling is so far the only method to clearly identify DGONC.
- If DNA methylation profiling is not available, morphological features may provide an approximation.
General
- 1st described in 2020 by Deng et al
- Methylation defined tumour type
Numbers
- Mainly paediatric
- A median age of 9 years (range 1–75 years)
Location
- Supratentorial
- Temporal lobe (11/21 cases).
Clinical features
- Not specific but depends on location of tumour in the brain
Pathology
- Lack of
Immunophenotype
- Diffusely OLIG2-positive in most cases
- GFAP-negative.
Origin
- Because the morphological and immunohistochemical features of DGONC are similar to those of CNS neuroblastoma, it is possible that DGONC represents a type or subtype of a CNS embryonal tumour. Larger series are needed for a definite classification
Genetics
- Monosomy 14
Radiological
- CT
- Internal calcification
- MRI
- Well-defined cortical or subcortical supratentorial masses
- Hyperintense on T2w/FLAIR
- Little or no contrast enhancement
- Low ADC values centrally
- An 11-year old boy presented with seizure.
- A mass in the right medial frontal lobe shows heterogeneous hyperintensity on T2w (A) and FLAIR (B).
- Small cysts are noted.
- Diffusion shows heterogenous signal but a small focus of low ADC (C).
- The tumour shows small foci of enhancement on T1w-CE (D)
Prognosis
- The 5-year survival rate: 89%
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