General
- Has been introduced as a provisional type in the WHO 2021 classification.
- CRINET represents a SMARCB1-deficient non-rhabdoid tumour with molecular similarities to the ATRT-TYR subgroup, but distinct histopathological features and a favour-able long-term outcome compared to ATRT-TYR
Definition
- Essential:
- Highly cellular tumour characterised by the presence of cribriform strands and ribbons AND
- Loss of nuclear SMARCB1 protein expression of tumour cells
- Desirable:
- Distinct expression of EMA highlighting cell surfaces
- Caveat:
- The distinction of CRINET from the AT/RT-TYR subgroup Is not fully established
Numbers
- Aged between 10 and 26 months
- M:F=1.5:1
Location
- Vicinity of the fourth, third, or lateral ventricles
Pathology
- Cribriform neuroepithelial tumour.
- A highly cellular tumour composed of relatively small cells arranged in cribriform strands, and trabeculae of varying thickness, forming well-defined surfaces.
Genetic pathogenesis
- 1st hit
- Losses on chromosome 22q affecting the SMARCB1 region are the only recurrent chromosomal alteration
- 2nd Hit
- SMARCB1 point mutations, as well as deletions of exons 7 and 8 or duplication of exon 6
Radiology
- A large intraventricular mass
- both solid and cystic components
- Heterogenous enhancement
- hydrocephalus as a presenting feature
Prognosis
- Many patients with CRINET respond well to therapy and experience long-term survival.
- The overall survival of 10 patients was found to be significantly longer than that of 27 patients with AT/RT-TYR
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