General
- <5 % of all intracranial neoplasm
- Diagnostic flowchart segregated by immunophenotype, location and genetic profile.
Abbreviations:
- MVNT: Multinodular and vacuolating neuronal tumors, DGONC: Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters, MGNT: Myxoid glioneuronal tumor, DLGNT: Diffuse leptomeningeal glioneuronal tumor, IHC: Immunohistochemistry, SYP: Synaptophysin, αINA: Alpha-internexin, NFP: Neurofilament protein, Cbr: Cerebrum, SP: Septum pellucidum, LEP: Leptomeninges, DD: Differential diagnosis, GG: Ganglioglioma, GC: Gangliocytoma, OLG: Oligodendroglioma, NC: Neurocytoma, DNT: Dysembryoplastic neuroepithelial tumor
Glioneuronal and neuronal tumors
- a diverse group of tumors, featuring neuronal differentiation
- “Good Dogs Don’t Dig Pits, Rather Make Dens, Growling, Munching, Dreaming, Catching Every Cat”.
Good | Ganglioglioma (GG) |
Dogs | Desmoplastic infantile ganglioglioma / desmoplastic infantile astrocytoma |
Don't | Dysembryoplastic neuroepithelial tumor (DNT/DNET) |
Dig | Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters (DGONC) |
Pits | Papillary glioneuronal tumor |
Rather | Rosette-forming glioneuronal tumor |
Make | Myxoid glioneuronal tumor (MGNT) |
Dens | Diffuse leptomeningeal glioneuronal tumor (DLGNT) |
Growling | Gangliocytoma (GC) |
Munching | Multinodular and vacuolating neuronal tumor (MVNT) |
Dreaming | Dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease) |
Catching | Central neurocytoma |
Every | Extraventricular neurocytoma |
Cat | Cerebellar liponeurocytoma |
Longstanding or long-term epilepsy associated tumours (LEAT)
- Associated with chronic or pharmacoresistant epilepsy.
- Made up of
- Gangliogliomas
- Dysembryoplastic neuroepithelial tumours (DNT)
- Pilocytic astrocytomas
- Pleomorphic astrocytomas
- Angiocentric glioma (ANET)
- Some diffuse gliomas
Low-grade epilepsy-associated neuroepithelial tumours’
- Since most cases undergo surgery before the criterion historically used to define ‘long- term’ epilepsy (>2 years) has been met
Tumor | % of Primary Brain Tumors (Adults and Children) | Approximate Seizure Frequency |
DNET/ganglioglioma | 1% | 80-100% |
Low grade glioma | 9% | 60-85% |
Brain metastasis | N/A | 24% (melanoma 67%) |
Glioblastoma | 17% | 25-40% |
Meningioma | 34% | 25-40% |
Summary
Feature | Ganglioglioma | Desmoplastic infantile ganglioglioma/ desmoplastic infantile astrocytoma | Dysembryoplastic neuroepithelial tumour (DNET) | Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters | Papillary glioneuronal tumor | Rosette-forming glioneuronal tumor | Myxoid glioneuronal tumor (MGNT) | Diffuse leptomeningeal glioneuronal tumor (DLGNT) | Multinodular and vacuolating neuronal tumor (MVNT) | Gangliocytoma (GC) | Dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease) | Central neurocytoma | Extraventricular neurocytoma | Cerebellar liponeurocytoma |
Age | 8.5-25 years | 0.5 | 20 | 9 | 23 | Wide range | Children | 28.5 | Wide range | 50 | ||||
Presentation | Seizures | HCP | Seizures | Seizure | HCP and seizures | HCP + Cerebellar signs | HCP and seizures | HCP and seizures | Incidental, seizures and headaches | Seizures | HCP + Cerebellar signs | HCP | Seizures and headaches | HCP + Cerebellar signs |
Microscopic | Biphasic - Dysplastic ganglion cells - Neoplastic glial cells. | Biphasic: - Desmoplastic stroma neoplastic astrocytes - Mature neuronal component +/- aggregates of poorly differentiated cells | - Specific glioneuronal element - Focal cortical dysplasia | nil | Biphasic - Astrocytic - Neuronal differentiation pseudostratified layer of flattened or cuboidal glial cells with scant cytoplasm around hyalinized blood vessels | Biphasic - Uniform neurocytes forming rosettes and/ or perivascular pseudorosettes - Astrocytic in nature and resembling pilocytic astrocytoma. | Oligodendrocyte-like cells in a myxoid stroma reminiscent of DNET | Biphasic - Leptomeningeal growth, an oligodendroglial-like cytology, - Some neuronal differentiation | Neuroepithelial cells with stromal vacuolation in a nodular formation | Neoplastic ganglion cells, often with dysplastic features | Diffuse enlargement of the molecular and internal granular layers of the cerebellum, which are filled by ganglionic cells of various size | Cells are typically uniform and round with a salt and pepper finely speckled chromatin | Small uniform cells that demonstrate neuronal differentiation | Advanced neuronal/neurocytic differentiation and focal lipoma-like changes |
Grade | 1, 3 | 1 | 1 | 1 | 1 | 1 | 1 | Low or high | 1 | 1 | 1 | 2 | 2 | |
Location | Temporal lobe | Frontal/parietal | Temporal lobe | Temporal lobe | Temporal and frontal lobe | Midline 4th ventricle and/or aqueduct | Midline Septum pellucidum | Leptomeninges (spine or cranial) | Supratentorial inner surface of otherwise normal cortex | Throughout CNS | Cerebellum | Lateral ventricle | Cerebral hemispheres | Cerebellum |
Radiology | Calcified Solid cystic | Calcification Solid cystic | Calcification | Calcification little or no contrast enhancement | T1+C avid but heterogeneous enhancement of the solid nodule Solid cystic | Solid-cystic | If it shows partially suppressed signal at the centre of the lesion resembling a T2-FLAIR mismatch | T2 tiger stripe | A focus of central FLAIR suppression within the vacuolated areas can increase diagnostic confidence | Calcification Solid cystic | Calcification enhancement is rare | Calcification Solid cystic | Circumscribed, Calcification | T1: Iso/hypointense with patchy areas of hyperintensity corresponding to regions of high lipid content |
Mutation | BRAF V600E | - BRAF V600E - RAF1 | - Gains of whole Chr 5 and 7 - BRAF V600E | - Monosomy Chr 14 - Specific methylation profile | Translocation, t(9;17)(q31;q24), → SLC44A1-PRKCA fusion oncogene | - NF1 - Missense mutation in exon 20 of PIK3CA - FGFR1 mutation | PDGFRA gene mutation | KIAA1549-BRAF fusion | PTEN | MYCN gain | FGFR1::TACC1 fusion | Loss of chromosomes 14 and 2p | ||
Syndrome | Peutz-jegher syndrome NF1 and 2 | Nil | NF1 XYY syndrome | Cowden syndrome | ||||||||||
Survival | Recurrence-free survival rate as high as 97% at 7.5 years. | ?? | Good Low malignant transformation | 5-year survival rate: 89% | Good prognostic factors Gross total resection | Curable with gross total resection | 33% live for more than 10 yrs | Benign nature | Benign tumours with good outcomes | Total resection is often curative | Benign and has a low rate of recurrence | 5 yr survival 48% |
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