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Optic Pathway Glioma

 

 

Incidence

5% of all childhood intracranial tumors are optic pathway gliomas1.

Generally low grade tumors, but follow a variable clinical course.

Most prevalent in young children:

  • 25% of all cases occurring before 18 months
  • 50% before 5 years
  • 75% within the first decade of life.

The mean age of presentation in one series was just over 8 years of age.  

These tumors may involve many different parts of the optic pathway:

  • 20-25% of tumors involve the optic nerves alone
  • 20-40% involve the optic chiasm (alone or in combination with cranial nerves)
  • 30-60% involve both the optic chiasm and the hypothalamus

 

Table : Incidence of various features of optic nerve gliomas.

Feature

Incidence

Proportion of pediatric intracranial tumors

5%

Before 18 months

25%

Before 5 years

50%

Before 10 years

75%

Median age

5 years

Involving optic nerves alone

20-25%

Involving optic chiasm (and/or optic nerves)

20-40%

Involving optic chiasm and hypothalamus

30-60%

Racial bias

None

Gender bias

Slight female predominance

Neurofibromatosis (NF)

  • Associated with the development of optic pathway gliomas
  • Type 1 NF is an autosomal dominant disorder characterized by abnormalities in ectodermal tissue growth.
  • 25-40% of optic gliomas occur in children with NF-1, and of children with NF-1, about 10% develop optic gliomas.

 

 

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