Low grade gliomas

Question 1

What are Low Grade gliomas?

Answer 1

Diffuse astrocytoma
Oligodendroglioma

Question 2

What are High Grade gliomas?

Answer 2

Glioblastoma
Astrocytoma

Question 3

What are Benign gliomas?

Answer 3

Pituitary
Meningioma

Question 4

Where do low grade gliomas originate?

Answer 4

Develop from glial cells (neuroglial cells)
Glia (Greek), Glue (English)
NOT nerve cells (neurons) – not directly involved with electrical signalling and synaptic interactions
Glial cells provide support and protection to neurons
Ratio of 3:1 glial cell:nerve cell > large number of glial cells in the brain
Do not have axons or dendrites

Question 5

Types of glial cell

Answer 5

Astrocytes (biggest glial cell)
Oligodendrocytes
Microglial cell
Schwann cell
Ependymal cell

Question 6

Presenting symptoms

Answer 6

Depends upon location of tumour (Slow growing undetected until cause symptoms due to growth)

Less likely focal neurological deficits e.g. weakness, aphasia
(Cells infiltrate (not destroy/compress cortex))

Headaches
(increased pressure due to obstruction – hydrocephalus (vision disturbances, nausea & vomiting) which raises ICP)

Seizures
(Partial/focal/tonic-clonic (grand mal))

Aphasia – language disorder, expression and comprehension

Hydrocephalus isa neurological disorder caused by an abnormal build-up of cerebrospinal fluid in the ventricles deep within the brain. This excess fluid causes the ventricles to widen, putting harmful pressure on the brain’s tissues

Question 7

Investigations

Answer 7

Clinical:
Full medical history
Aetiological factors - very little links aetiologically (main one > radiation)

Histopathology:
Via biopsy
May only be completed when having surgery
Stereotactic needle biopsy
Atypia - differentiation of cells > how typical they look under microscope
Anaplasia (cell differentiation)
Microscope proliferation
Necrosis

Imaging:
CT
Low tumour density
Oligodendrogliomas – calcification & patchy contrast enhanced (not ring enhanced HGG)
MRI
T2 weighted, FLAIR, DWI series & T1 pre- and post- contrast
MRI perfusion & MR spectroscopy – if concerns about possible high grade transformation

Question 8

Oligodendrogliomas

Answer 8

IDH mutation AND 1p/19q co-deletion

Favourable prognosis

Question 9

Astrocytoma

Answer 9

IDH mutation NO 1p/19q co-deletion probable TP53 mutations & ATRX mutation

Favourable prognosis

Question 10

NO IDH mutation NOR 1p/19q co-deletion

Answer 10

Least favourable prognosis

Question 11

Risk Factors, Prognostic Factors

Answer 11

Age ≥40 higher risk

Performance Status

Presenting Symptoms
(Seizures better prognosis as earlier diagnosis
Neurological deficits – poorer prognosis)

Tumour size & location (surgical location - ease of removal)

Question 12

Management (Symptomatic)

Answer 12

Timing remains controversial
~6mths from radiological diagnosis

Safe maximal resection (most you can remove safely)
(Awake craniotomy inc language and functional monitoring
Neuroradiological support
Intraoperative neurophysiological monitoring
Intraoperative image guidance)

Question 13

Management (Asymptomatic)

Answer 13

Consider active monitoring

Biopsy