"The aetiology of these tumours has not been established, and several hypotheses have been advanced. Proposed origins include Schwann cells of perivascular autonomic nerve plexuses, neural crest cells or Schwann cell precursors displaced into the brain during embryogenesis, and metaplasia of multipotent mesenchymal or pial cells 3,6,7,9,11,. The young age of many patients has been cited in support of a developmental origin 10."
"The imaging differential diagnosis depends on location and includes 6,7,9,10,12,13:"
"These tumours are not currently designated as a separate tumour type in the 2021 (5th edition) WHO classification of CNS tumours, where they are acknowledged only in passing in chapter 8 (Schwannoma). However, the recent identification of a distinctive DNA methylation profile and the presence of a gene fusion involving the Vestigial-like family (VGLL) of genes (see below) have been used to propose that these tumours be designated as intraparenchymal CNS schwannoma (VGLL altered) 8."
"EMA: negative"
"GFAP: usually negative"
"VGLL-fused tumours have shown variable GFAP expression, MAP2c positivity, and weak CD34 staining 8."
"Importantly, alterations typical of conventional schwannomas, such as NF2 mutation, 22q loss, and LATS1/2 or SOX10 alterations, are absent in intraparenchymal schwannomas 8,12."
Expected headings
"Associations"
"These tumours are not currently designated as a separate tumour type in the 2021 (5th edition) WHO classification of CNS tumours, where they are acknowledged only in passing in chapter 8 (Schwannoma). However, the recent identification of a distinctive DNA methylation profile and the presence of a gene fusion involving the Vestigial-like family (VGLL) of genes (see below) have been used to propose that these tumours be designated as intraparenchymal CNS schwannoma (VGLL altered) 8."
"These tumours are not currently designated as a separate tumour type in the 2021 (5th edition) WHO classification of CNS tumours, where they are acknowledged only in passing in chapter 8 (Schwannoma). However, the recent identification of a distinctive DNA methylation profile and the presence of a gene fusion involving the Vestigial-like family (VGLL) of genes (see below) have been used to propose that these tumours be designated as intraparenchymal CNS schwannoma (VGLL altered) 8."
"The aetiology of these tumours has not been established, and several hypotheses have been advanced. Proposed origins include Schwann cells of perivascular autonomic nerve plexuses, neural crest cells or Schwann cell precursors displaced into the brain during embryogenesis, and metaplasia of multipotent mesenchymal or pial cells 3,6,7,9,11,. The young age of many patients has been cited in support of a developmental origin 10."
"Histology is that of a conventional schwannoma: interlacing fascicles of spindle cells with elongated nuclei, nuclear palisading with Verocay bodies, alternating compact (Antoni A) and loose myxoid (Antoni B) areas, hyalinised vessels and a dense pericellular reticulin network 6,7,9,12. Degenerative ("ancient") nuclear change, haemosiderin deposition and mineralisation may be seen, while mitotic activity is characteristically low 6,8. In the molecularly defined series, a fasciculo-nodular growth pattern with interspersed CNS tissue was typical 8."
"Importantly, alterations typical of conventional schwannomas, such as NF2 mutation, 22q loss, and LATS1/2 or SOX10 alterations, are absent in intraparenchymal schwannomas 8,12."
"Radiologic appearances of intracerebral schwannoma are non-specific but most often include well-defined margins, cystic components, enhancement, and surrounding vasogenic oedema 1,2,4,5."
"T1 C+: strong enhancement of the solid component, homogeneous or heterogeneous 2,6,10-12"
"Recurrence or regrowth of residual tumour is occasionally encountered, particularly after subtotal resection of brainstem lesions, and has been successfully controlled with fractionated radiotherapy 12. Rare malignant examples pursue a rapidly progressive course despite surgery, radiotherapy and chemotherapy 11."
"History and etymology"
"glioneuronal tumours (e.g. ganglioglioma and gangliocytoma)"