Other CNS embryonal tumours
| 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) |
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.
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
- often infants.
- Tumors can be huge.
- 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
CNS neuroblastoma:
- Groups of neurocytic cells.
- Variable neuropil-rich stroma.
- Small round blue cells.
HGNET-BCOR:
- Circumscribed growth.
- Perivascular pesudorosettes.
- Fibrillary areas resembling glioma.
- Palisading necrosis.
- Absence of microvascular proliferation.
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 variable +ve.
- BCOR +ve.
- Syn -ve.
- GFAP -ve.
- EMA: dots +ve.
- NEUN +/-ve.
DDx:
- AT/RT
- ETMR
- Anaplastic ependymoma
- H3F3A G34-mutated Glioblastoma
- Metastasis of Ewing sarcoma
- ↑ "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.