Other CNS embryonal tumours
Other CNS embryonal tumor, was introduced in the WHO 2016 classification of CNS tumors. Some of these tumors of this category has been previously designated as CNS-PNET but this terminology has been abandoned.
| Other CNS embryonal tumours | |
|---|---|
| Diagnosis in short | |
 Other CNS embryonal tumorH&E stain. | |
|
| |
| Synonyms | CNS-PNET |
| LM DDx | small round blue cell tumours |
| IHC | S-100 +ve, Syn +/-ve |
| Site | brain, spinal cord |
|
| |
| Prevalence | rare - typically in children and young adults |
| Prognosis | poor (WHO Grade IV) |
General
Other CNS embryonal tumours are a group of primitive neuroeptithelial tumors that are to be classified in distinct molecular groups in the future. Currently it is a exlcusion criteria encompassing four morphological subgroups
- CNS neuroblastomas
- CNS ganglioneuroblastomas.
- often characterized by FOXR2 fusions: CNS neuroblastoma with FOXR2 activation (NB‐FOXR2)
- CNS medulloepithelioma.
- but absence of C19MC alteration, otherwise classified as ETMR
- CNS embryonal tumour, NOS
- Similarities to astroblastoma: High‐grade neuroepithelial tumours with MN1 alteration (HGNET‐MN1)
- NUTM1-positive IHC: Ewing's sarcoma family tumour with CIC alteration (EFT‐CIC)
- BCOR-positive IHC: HGNET BCOR‐altered neuroepithelial tumours
Currently four distinct subtypes can be discriminated by molecular analysis: NB-FOXR2, HGNET-MN1, EFT-CIC and HGNET-BCOR.[1]
Histology
- HGNET-BCOR:
- Circumscribed growth.
- Perivascular pesudorosettes.
- Fibrillary areas resembling glioma.
- Palisading necrosis.
IHC
CNS Ganglioneuroblastoma + Neuroblastoma
- Syn -/+ve.
- Vim -ve.
- GFAP usu -ve.
- MIB-1 usu high.
Medulloepthelioma
- Syn +/-ve.
- NF +/-ve.
- GFAP usu -ve.
- CK may be focally +ve.
HGNET-BCOR [2]
- OLIG +ve.
- BCOR +ve.
- Syn -ve.
- GFAP -ve.
- EMA: dots +ve.
- NEUN +/-ve.
DDx:
- AT/RT
- ETMR
- Anaplastic ependymoma
- H3F3A G34-mutated Glioblastoma
- ↑ "New Brain Tumor Entities Emerge from Molecular Classification of CNS-PNETs". Cell 164 (5): 1060–1072. February 2016. doi:10.1016/j.cell.2016.01.015. PMC 5139621. PMID 26919435. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5139621/.
- ↑ "High-grade neuroepithelial tumor with BCOR exon 15 internal tandem duplication-a comprehensive clinical, radiographic, pathologic, and genomic analysis". Brain Pathol. 30 (1): 46–62. January 2020. doi:10.1111/bpa.12747. PMID 31104347.