Ependymomas

Tumors arising from the ependymal cells lining the CSF pathways.
Ependymal cells are found in the :

• Cerebral Ventricles
  
• Vestigial Central Canal

Most commonly arise in the periventricular area.
Site of origin:

• Infratentorial location (60%) > Supratentorial location (40%)
  
• MC origin 4th ventricle.
  
• 4th ventricle > Spinal cord > Lateral Ventricles > 3rd Ventricles
  
• In supratentorial location tumors are intraventricular in 50% and parenchymal in 50%

Histology:

• Three Grades are known:
  
  • Grade I : Myxopapillary (arise in the cauda equina and filum terminale - excellent prognosis with excision alone)
    
  • Grade II: Majority of ependymomas with an intermediate prognosis
    
    • Cellular
      
    • Papillary
      
    • Clear Cell
      
    • Tanycytic
      
  • Grade III: Anaplastic astrocytoma with intermediate prognosis.

Clinical Features:
MC present with features of raised ICT
Account for 5% of the adult gliomas and 10% of childhood CNS tumors
Have bimodal incidence peak:

• 5 years
  
• 34 years

Diagnosis:

• CT / MRI are the imaging modality of choice
  
• CSF examination is done to rule out CSF spread
  
• Presence of a calcified mass leison in the ventricle correlates with an ependymoma
  
• Surgical excision is necessary for diagnosis

Treatment:

• MSR followed by adjuvant RT
  
• Not needed in Gr I ependymomas
  
• In others needed
  
• Need for CSI determined by risk of CSF spread:
  
  • Depends on:
    
    • Location : Infratentorial (5%) > Supratentorial (3%)
      
    • Grade : High grade (8%) > Low grade (4%)
      
  • Infratentorial, high grade leisons have 14%incidence of CSF spread.
    
  • Indications of CSI in ependymomas:
    
    • High grade, infratentorial leisons
      
    • Positive CSF cytology
      
    • Demonstrable radiological extension
      
    • All ependymoblastomas.
      
  • Radiation Dose:
    
    • 54 Gy by localized field around the tumor + margins
      
    • 30 -36 Gy to CSI if indicated
      
  • Radiation results:
    
    • With RT + Sx survival for Grade II ependymomas is in the range of 60 - 80% at 5 years
      
    • In case of anaplastic ependymomas the survival is lesser to the tune of 20 - 40%.
      
    • Ependymoblastomas have a poorer prognosis.
      
    • Pattern of failure: With localized fields predominent pattern of failure is local.

Future efforts:

• Integration of chemotherapy like TMZ - so far CCT has no benefit in Ependymomas
  
• Boosting the tumor volume with more conformal radiation techniques:
  
  • 3D CRT / IMRT
    
  • Stereotactic Radiosurgery
    
  • Hyperfractionated RT

Blogged with Flock