Astrocytomas

Related Subjects: |Brain tumours |Astrocytomas |Brain Metastases |Tuberous sclerosis |Turcot's syndrome |Lhermitte Duclos Disease |Oligodendroglioma |Acute Hydrocephalus |Intracranial Hypertension | Primary CNS Lymphoma (PCNSL)

About

• Poor prognosis except in Grade I

Risk factors

• Exposure to ionising radiation
• Neurofibromatosis type 1 and 2 (glioma)
• Tuberous sclerosis (astrocytoma)
• Li Fraumeni (malignant glioma)
• Turcot syndrome (malignant glioma)

Aetiology

• Faulty tumour suppressor genes
• Oncogenes
• Amplification of EGFR gene
• Inactivation of p53 gene

Classification Low to High Grade

• Grade I Benign
• Grade II Diffuse
• Grade III Anaplastic
• Grade IV Glioblastoma multiforme

Clinical

• See Brain tumours

Imaging

Difficulties of Diagnosis Tumour vs Stroke

	Day 1: admitted suspected stroke but some atypical features. Patient improved and discharged home
	Day 15: clinical worsening
	Day 18: clinical worsening
	Day 21
	Day 21
	Day 21
	Day 21 with contrast

Differential of Butterfly tumour across the Corpus: pre and post contrast

• High grade Astrocytoma, usually a Glioblastoma (WHO grade IV)
• Primary CNS lymphoma (consider HIV)
• Cerebral Toxoplasmosis (consider HIV)

Low grade Astrocytomas

• These tumours are found in the Cerebrum and cerebellum (commoner in children), Hypothalamus, Optic nerve, Chiasm, Pons
• Grade I Benign: seen in childhood with excellent prognosis after removal. Also called juvenile pilocytic astrocytomas or subependymal giant cell astrocytoma. Pilocytic have spindle-shaped cells. May involve the cerebellum. Well demarcated from the brain.
• Grade II: Astrocytoma has a prognosis of 5-6 years. Intermediate in histology. Well-differentiated slow-growing tumour. Young Adults affected.
• MRI may show sharply demarcated pilocytic tumours with hypointense T1 and hyperintense T2. Fibrillary tumours are less well-demarcated. Maybe cyst formation and calcium. May be limited contrast enhancement.
• As mentioned above some Grade I tumours in children can be resected with an excellent prognosis. In the remainder, Survival may be up to 5-6 years. Some tumour resection especially of cystic lesions. Total excision may be possible in some with improved survival. With time low-grade gliomas become more malignant. Radiotherapy may also be given. Side effects of early radiation may be later dementia and hypopituitarism. A watch and wait strategy may be adopted for slow-growing tumours. Seizure management.

High grade astrocytomas

• Includes Grade III Anaplastic and Grade IV Glioblastoma multiforme (malignant aggressive tumours) which form 20% of all intracranial tumours. Mean age 56-60 years old. Grade III has a median survival of less than 3 years and Grade IV less than 1 year.
• Derived from glial cells - astrocytes. Most arise in white matter and infiltrate the brain. Grey, reddish-brown appearance. May contain a haemorrhage. Surrounding oedema.
• Found mainly in the Cerebrum most commonly and Brainstem, cerebellum, cord. CT/MRI shows tumour mass +/- bleeding, distortion, midline shift which enhances with contrast
• Only 10% survive beyond 2 years. Prognosis is very poor. Palliation, Dexamethasone 4 mg every 4-6 hours. Anticonvulsants for seizures. Cranial irradiation and chemotherapy may extend life in some cases