Neurosurgery notes/Tumours/Gliomas, Glioneuronal Tumors, and Neuronal Tumors/Glioneuronal and neuronal tumours/Papillary glioneuronal tumour

Papillary glioneuronal tumour

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Glioneuronal and neuronal tumours

Definition

  • Essential:
    • Biphasic histological and immunophenotypic pattern with AND
      • Pseudopapillary glial lining
      • Interpapillary neuronal components
    • PRKCA gene fusion (mostly SLC44A1::PRKCA) AND (for unresolved lesions)
      • Methylation profile of papillary glioneuronal tumour
  • Desirable:
    • Well-delineated, solid and cystic tumour
  • Caveat:
    • Diagnosis should be heavily weighted towards molecular findings because morphological analyses frequently result in mistyping

Numbers

  • <0.02% of all intracranial tumours
  • Median age 23 yrs
    • 35% aged < 18 years and
    • 60% were aged < 26 years.
  • Male : Female 1: 1

Grading

  • WHO Grade 1
  • Some can progress with atypical histology

Clinical features

  • Headaches and seizures
  • Rare neurological deficits

Localisation

  • Supratentorial near ventricles
    • Temporal and frontal lobe
    • Can grow intraventricularly

Origin

  • Carangelo et al. 2015: Multipotent precursor cells capable of divergent glioneuronal differentiation, likely arising from subependymal stem or progenitor cells in the periventricular region.

Radiology

General

  • Features on imaging are very similar to ganglioglioma.
  • Circumscribed cystic or solid mass with contrast enhancement

MRI

  • T1: isointense to hypointense
  • T2: inhomogeneously hyperintense
  • FLAIR:
    • Inhomogeneously hyperintense nodule
    • Cystic components may suppress
  • T1 C+: avid but heterogeneous enhancement of the solid nodule
Images
A close-up of a brain scan AI-generated content may be incorrect.
T1
A close-up of a mri scan AI-generated content may be incorrect.
T2
A close-up of a mri scan AI-generated content may be incorrect.
T1+C
A mri of a brain AI-generated content may be incorrect.
DWI
A mri of a brain AI-generated content may be incorrect.
Flair
A close-up of a brain scan AI-generated content may be incorrect.
ADC mapping
A mri of a brain AI-generated content may be incorrect.
Gradient echo
 

Histopathology

Macroscopic

  • Solid and cystic elements
  • Grey and friable

Microscopic

  • Prominent pseudopapillary architecture
  • A single or pseudostratified layer of flattened or cuboidal glial cells with round nuclei and scant cytoplasm around hyalinized blood vessels
  • Intervening collections of neurocytes and medium-sized ganglion cells with accompanying neuropil.
  • Low Ki-67 proliferation index/MIB-1 index ~1-2%
Fig. 6.26 Papillary glioneuronal tumour. A At low magnification, the tumour shows typical papillary structures; vessels are hyalinized and haemosiderin deposits are obvious. B Characteristic pseudopapillary structure with hyalinized blood vessels.
Papillary glioneuronal tumour. A, At low magnification, the tumour shows typical papillary structures; vessels are hyalinized and haemosiderin deposits are obvious. B, Characteristic pseudopapillary structure with hyalinized blood vessels.
Fig. 6.28 Papillary glioneuronal tumour. A Mitotic figures are rarely seen. B Ganglioid cells and neurocytes with fibrillary neuropil. C Minigemistocytes are occasionally observed In some cases.
Papillary glioneuronal tumour. A, Mitotic figures are rarely seen. B, Ganglioid cells and neurocytes with fibrillary neuropil. C, Minigemistocytes are occasionally observed in some cases.

Immuno-phenotype

  • Cuboidal glial cells:
    • GFAP: positive
    • S100: positive
    • Nestin: positive
  • Neuronal components:
    • Synaptophysin: positive
    • Neurone-specific enolase: positive
    • Class III beta-tubulin: positive
    • Chromogranin-A expression: negative

Genetic profile

  • Translocation, t(9;17)(q31;q24), → SLC44A1-PRKCA fusion oncogene
    • PRKCA encodes protein kinase C alpha (PKCA), which is a member of the family of calcium- and phospholipid-dependent serine/threonine kinases that are involved in the МАРК signalling pathway

Prognosis

  • Good prognostic factors
    • Gross total resection
    • 82% 2 yrs. PFS rate
  • Poor prognostic factors
    • Anaplastic features: mitoses, microvascular proliferation, necrosis, high proliferation rate
  • Recurrence is not uncommon
  • Spread: rare

Differential diagnosis

  • Other cystic solid tumours
    • Gangliogliomas and gangliocytomas
    • Pleomorphic xanthoastrocytoma
    • Pilocytic astrocytoma
    • Diffuse astrocytoma, particularly gemistocytic astrocytoma and oligodendrogliomas (if calcification prominent)
    • Rosette-forming glioneuronal tumours (particularly if midline/posterior fossa)