Definition
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• Well differentiated neuroepithelial tumors composed of neoplastic ganglion cells (gangliocytoma) or combination of neoplastic ganglion cells and neoplastic glial component (ganglioglioma)

Epidemiology
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• <2% of all brain tumors
• Ages 2 months to 70 years, with predilection for children and young adults

Sites
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• Throughout CNS, but >70% involve the temporal lobe

Grading
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• Gangliocytoma, WHO grade I
• Ganglioglioma, WHO grade I
• Anaplastic ganglioglioma, WHO grade III
• Criteria for grade II are not yet established

Clinical features
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• Associated with long term epilepsy

Radiology
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• Circumscribed solid mass or cyst with a mural nodule
• Variable enhancement, variable calcification

Radiology images
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Temporal lobe tumor

Various images

Case reports
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• 48 year old woman with acromegaly and intrasellar tumor (Arch Pathol Lab Med 2005;129:415)

• Infant with brainstem ganglioglioma (J Pediatr Neurosci 2013;8:41)
• 4 year old boy with seizures (Arch Pathol Lab Med 2003;127:e387)
• 30 year old man with spinal tumor (University of Pittsburgh Case 142)
• 36 year old woman with coexisting dysembryoplastic neuroepithelial tumor (Arch Pathol Lab Med 1999;123:247)
• 51 year old man with ganglioglioma containing neurofibrillary tangles (University of Pittsburgh Case 66)
• Various cases with combined pleomorphic xanthoastrocytoma (Arch Pathol Lab Med 2000;124:1707, Am J Surg Pathol 1997;21:763)

• 6 year old girl with composite grade III/IV ganglioglioma and giant cell glioblastoma (Arch Pathol Lab Med 1999;123:342)
• 7 year old girl with dissemination to spinal cord (Surg Neurol 1998;49:445)
• 45 year old woman with 5 month history of headache and dizziness (J Korean Med Sci 2007;22:S139)
• 53 year old woman with metastasis through a ventriculoperitoneal shunt (Pathol Int 1999;49:258)
• 59 year old man with sarcomatous component (Neuropathology 2002;22:40)

Gross description
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• Solid or cystic
• No hemorrhage or necrosis

Gross images
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Hypothalamo-infundibular region

Various images

Micro description
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• Compact growth pattern
• The hallmark of ganglion cell tumors is the presence of dysplastic/neoplastic ganglion cells that are identified by:
  • Loss of cyto-architectural organization
  • Abnormal (subcortical) localization
  • Clustering
  • Large neurons (cytomegaly)
  • Coarse peripherally aggregated Nissl substance
  • Bi- or multinucleated neurons with prominent nucleoli

• Neoplastic ganglion cells
• Stroma: finely fibrillar neuropil-rich

• Neoplastic ganglion cells
• Neoplastic glial component:
  • Constitutes the proliferative component of the tumor (Ki-67 is 1.1 to 2.7%)
  • Astrocytic: resemble fibrillary astrocytoma or pilocytic astrocytoma.
  • Variable lobular architecture
  • Rare mitoses, no necrosis
• Common features:
  • Perivascular lymphocytic cuffing
  • Rosenthal fibers and eosinophilic granular bodies
  • Microcysts
  • Rich reticulin network
  • Calcification
  • Glomeruloid vascular proliferation
  • Desmoplasia, especially with tumors involving the subarachnoid space

• Anaplastic changes involving the glial component
  • Increased mitotic activity
  • Vascular proliferation
  • Necrosis
• Anaplastic changes in neuronal component are rare

Micro images
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Gangliocytoma:

Nerve cells of variable size and shape

Tumor attached to dura (fig 1e)

Intrasellar tumor

Synaptophysin+ (fig 1f)

Ganglioglioma:

Large neurons

Reticulin stain

Variable sized astrocytes, nerve cells and calcification

Nesting pattern with delicate vasculature

 

Various images

Tumor with neurofibrillary tangles

Large, mature neurons +/- glial component

1: MRI shows temporal lobe mass with cystic component
2: prominent granular bodies, Rosenthal fibers and microcalcifications
3: like #2 plus large, binucleated ganglion cells and perivascular cuffing
4: NSE+

 

Synaptophysin

 

GFAP+ astrocytes and their processes

Anaplastic ganglioglioma:

Various images

Pleomorphic ganglion cells

Cytology images
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Ganglion cell with prominent nucleoli and neoplastic astrocytes

Positive stains
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• Ganglion cells: synaptophysin+, chromogranin+, NeuN+/-, neurofilament+, MAP2+, CD34+ (70-80%)
• Glial component: GFAP+

Electron microscopy description
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• Neurons with dense core granules are characteristic and diagnostically useful

Differential diagnosis
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• Cortical dysplasia and cortical tubers: no cyst or compact architecture
• Desmoplastic infantile ganglioglioma: markedly desmoplastic, smaller ganglion cells
• Dysplastic cerebellar gangliocytoma: site specific, associated with Cowden syndrome
• Hypothalamic hamartoma: classic location, non-enhancing
• Infiltrating glioma with entrapped neurons: no abnormal clustering or binucleation of the entrapped neurons
• Normal brain: organized, no dysplastic neurons
• Pilocytic astrocytoma: no neoplastic neurons
• Pleomorphic xanthoastrocytoma: pleomorphic astrocytes, +/- lipidization
• Subependymal giant cell astrocytoma: site specific, associated with tuberous sclerosis

Additional references
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• Neuronal and Mixed Neuronal-Glial Tumors of the Central Nervous System, Radiographics 2001;21:1533, Radiopaedia

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