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Ganglioglioma

Summary

  • Rare, slow-growing neuroepithelial tumour composed of neoplastic glial and neuronal cells
  • Most commonly occurs in children and young adults, typically presenting with seizures
  • Characteristic imaging findings include a cystic mass with a mural nodule, often in the temporal lobe1

Pathophysiology

  • Mixed neuronal-glial tumour with WHO grade 1 classification
  • Composed of dysplastic ganglion cells and neoplastic glial cells, typically astrocytic
  • Molecular alterations:
    • BRAF V600E mutation in approximately 50% of cases
    • CD34 expression in most cases
    • IDH½ mutations are rare

Demographics

  • Accounts for 0.4-1.3% of all central nervous system (CNS) tumours
  • Peak incidence in children and young adults (median age 20-30 years)
  • Slight male predominance (male:female ratio 1.2:1)
  • Most common location: temporal lobe (70%), followed by frontal and parietal lobes

Diagnosis

  • Clinical presentation:
    • Seizures (most common, 80-90% of cases)
    • Headaches
    • Focal neurological deficits
  • Histopathology:
    • Biphasic pattern with neuronal and glial components
    • Dysplastic neurons with abnormal clustering and orientation
    • Perivascular lymphocytic cuffing
  • Immunohistochemistry:
    • Neuronal markers: synaptophysin, NeuN
    • Glial markers: GFAP
    • CD34 positivity in most cases

Imaging

  • CT findings:
    • Hypodense or isodense mass
    • Calcifications in 30-50% of cases
    • Variable contrast enhancement
  • MRI findings:
    • T1: hypointense to isointense
    • T2/FLAIR: hyperintense
    • Cystic component with mural nodule in 50-60% of cases
    • Variable gadolinium enhancement, often in the solid component
    • Minimal perilesional oedema
  • Advanced imaging:
    • MR spectroscopy: elevated choline, decreased NAA
    • Perfusion imaging: generally low relative cerebral blood volume

panels-1

  • 20-year-old patient presented with generalised tonic-clonic seizures.
  • Imaging showed a non-enhancing solid-cystic lesion in the right mesial temporal lobe with a single speck of calcification.
  • Histopathology following resection confirmed a ganglioglioma.

Treatment

  • Surgical resection is curative with excellent seizure outcomes; BRAF inhibitors for BRAF V600E-mutant recurrent disease

Differential diagnosis

Differential Diagnosis Distinguishing Feature
Dysembryoplastic Neuroepithelial Tumour (DNET) "Bubbly" or multinodular appearance; contrast enhancement uncommon; no mural nodule
Pleomorphic Xanthoastrocytoma Prominent contrast enhancement; dural tail sign; typically superficial location
Oligodendroglioma Calcifications common; "honeycomb" cortical pattern; more diffuse T2 signal
Pilocytic Astrocytoma More common in cerebellum; prominent enhancing mural nodule; Rosenthal fibres on histology
Focal Cortical Dysplasia No mass effect; cortical thickening with blurring of grey-white matter junction; no enhancing nodule
Desmoplastic Infantile Ganglioglioma Large cystic mass with dural involvement; typically in infants under 2 years

  1. Puget et al. Pediatric infratentorial ganglioglioma. 2015. Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery - Open in new tab. ↩