Neurosurgery notes/Tumours/Embryonal tumours/Other CNS embryonal tumors/CNS tumor with BCOR internal tandem duplication

CNS tumor with BCOR internal tandem duplication

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Other CNS embryonal tumors

Definition

  • Essential:
    • A malignant primary CNS tumour with a predominantly solid growth pattern uniform oval or spindle-shaped cells with round to oval nude, and a dense capillary network AND
    • An internal tandem duplication on exon 15 of BCOP AND (for unresolved lesions)
    • A DNA methylation profile aligned with CNS tumour with BCOR eternal tandem duplication

Numbers

  • Median age of diagnosis of 3.5 years
  • A balanced male:female ratio

Location

  • Cerebellar or cerebral hemisphere
  • Metastases generally absent at the time of diagnosis.
  • At relapse, however, leptomeningeal metastases and continuous spread along surgical tracts have been reported

Pathology

  • CNS tumor with BCOR internal tandem duplication is a neoplasm with a mostly solid growth pattern, uniform oval or spindle-shaped cells, a dense capillary network, focal pseudorosette formation, and an internal tandem duplication (ITD) in exon 15 of the BCOR gene.
Fig. 5 CNS tumor with BCORinternaltandem duplication is a neoplasm with a mostly solid growth pattern, uniform oval or spindle-shaped cells, a dense capillary network, focal pseudorosette formation, and an internal tandem duplication (ITD) in exon 15 of the BCOR gene. (A) High-grade neo- plasm with perivascular rosettes (H&E, and (B) strong, diffuse nuclear staining on BCOR immunohistochemistry (x100).
(A) High-grade neoplasm with perivascular rosettes (H&E, ×200)
(B) strong, diffuse nuclear staining on BCOR immunohistochemistry (×100).

Genetic

  • The ITD in BCOR produces an activating, gain-of-function event,
    • The specific mechanism by which this recurrent alteration drives tumour development remains unknown.
  • There is currently no consensus as to whether CNS tumours should be considered mesenchymal or neuroepithelial neoplasms because
    • The duplicated region in exon 15 of BCOR is identical to that of BCOR ITDs in clear cell sarcomas of the kidney, undifferentiated round cell sarcomas in infants, and primitive myxoid mesenchymal tumour of infancy .

Radiology

  • Imaging features
    • A solid
    • Circumscribed mass
    • Superficial location
    • Can have
      • Large internal cystic components
      • Necrosis
      • Intratumoral haemorrhage
  • T2: hyperintense
  • DWI: Restricted diffusion
  • T1 + C variable and heterogenous enhancement.
  • MR spectroscopy:
    • High choline peak, reduced NAA, and a lipid/lactate doublet
Images
  • A 5-year-old boy presented with vomiting and headaches.
  • Methylation class of CNS high-grade neuroepithelial tumour with BCOR alteration.
  • T2w (A) and FLAIR (B, D) show a hyperintense mass located within the peripheral aspect of the right cerebellar hemisphere.
  • Linear areas of contrast enhancement on T1wCE (C) are present.
  • There is partial effacement of the 4th ventricle and associated hydrocephalus
A close-up of a brain scan AI-generated content may be incorrect.

Prognosis

  • Overall survival was poor
  • Time to relapse can be prolonged up to 5 years after initial diagnosis