Glial neoplasms

 

- oligodendroglioma

- astrocytoma

- ependymoma

 

Terminology

- atypia

- pleomorphism

- cellularity

- differentiated

- anaplastic

- necrosis

- vascular proliferation

- mitotic figures / index

- MIB-1 index

- 1 structures

- 2 structures

- 3 structures

 

Diffuse/infiltrating astrocytoma

- WHO grade II - 10 years to demise

- 10-15% of astrocytic brain tumours

- 60% occur between 20-45 years of age

- cerebral hemisphere, brainstem in children

- astrocytes are most common glial cell in CNS, major proliferative cell

- MIB-1 usually < 1%

- Two courses:

- remain low grade

- transform to higher grade

 

Grading:

1- atypia, cellularity, pleomorphism

4- necrosis

3- vascular proliferation

2- mitotic activity

WHO grade is = (number of these factors + 1)

 

Anaplastic astrocytoma

- WHO gr III

- mean age 41, M:F is 1.8:1

- 2 structures - follow white matter, blood vessels

 

Glioblastoma multiforme

- WHO gr IV

- 1, occuring de novo - start 10 years later, faster history, smaller, more superficial

- 2, backgrd of lower grade lesion (progression) - p53 mutations

- most common, poor prognosis

 

Pilocytic astrocytoma

- WHO gr I

- most common in children

- discrete

- Rosenthal fibres

 

Oligodendroglioma

- WHO gr II

- MIB-1 < 5%

 

Anaplastic oligodendroglioma

- 1p19q - loss of heterozygosity - chemotherapy sensitivity improved

 

Ependymoma

- WHO gr II

- resectible, do not recur if completely resected

- children and post-fossa (4th ventricle) do worse

 

Anaplastic ependymoma

- WHO gr III

 

Myxopapillary ependymoma

- WHO gr I

- most common in filum terminale

- good outcome

 

Glio-neuronal tumours

- heterogeneous mix of tumours

- polymicrogyria

- white matter heterotopia

- "brain warts" - cortical verrucae

- cytological alterations

 

Dysembryoplastic neuroepithelial tumour (DNET)

- WHO gr I

- quasimalformative

- seizures

- most common found in resected temporal lobectomies for intractible seizures

 

Ganglioglioma / gangliocytoma

- temporal lobe, brain stem

- superficial, discrete

 

Papillary glioneuronal tumour

 

Superficial desmoplastic ganglioglioma / astrocytoma

- WHO gr I

- < 10 yr ago