Astrocytoma

Astrocytomas are neuroepithelial tumors (gliomas) that arise from the supportive tissue of the brain. These tumors are classified by the WHO into four separate grades depending on the extent of abnormality. Astrocytomas initially present with general symptoms including headaches and/or epileptic seizures, which are rapidly replaced by focal symptoms such as progressive paralysis or aphasia. Low-grade astrocytomas are usually localized, slow-growing, and occur predominantly in younger populations (children and adults aged 20–40). Grade IV astrocytomas, on the other hand, are rapidly growing glioblastomas, which are the most common brain tumors in adults aged 50–60. Diagnosis is established based on the patient's clinical history and MRI findings. The treatment for astrocytomas is surgical resection, which may need to be combined with radiotherapy and/or chemotherapy in higher grade tumors. The prognosis is usually poor for higher grade tumors regardless of whether they receive treatment, with a life expectancy of several months (maximum of 2 years). However, low-grade astrocytomas can often be completely cured with effective surgical resection.

WHO grade	Type	Age	Location	Symptoms	Imaging	Treatment	Prognosis
I	Pilocytic astrocytoma	Children and young adults (< 20 years)	Most common: posterior cranial fossa (infratentorial) Cerebellum Less common: optic pathway (optic glioma), hypothalamus, cerebral hemispheres (supratentorial)	Vomiting, ataxia Failure to thrive (impaired growth) Often associated with neurofibromatosis type I	Well-demarcated cystic lesion often with a bright contrast-enhancing solid nodule in the wall of the cyst MRI: T1 hypointense T2 hyperintense	Surgical resection	Good
	Optic glioma	Most frequently children (< 10 years)	Optic nerve or chiasm	Sporadic episodes of vision impairment Bulging of eyeball or impaired eye movements Often associated with neurofibromatosis type I	MRI: T1 hypointense T2 hyperintense	No treatment in asymptomatic patients with no signs of growth of tumor Surgical resection Radiotherapy of unresectable tumors , or after surgery	Good; however, many patients have significant long-term visual impairment.
II	Diffuse astrocytoma	20–40 years of age	Cerebral hemisphere	General clinical features of brain tumors (e.g., epileptic seizures)	MRI: T1 hypointense or isointense T2 hyperintense CT: hypodense, no contrast enhancement	Complete surgical resection often not possible ; resection until definable margins can be attempted Percutaneous radiotherapy for very diffuse, unresectable tumors	5-year survival rate: ∼ 34% without treatment ∼ 70% with radiation therapy
III	Anaplastic astrocytoma	30–50 years of age	Cerebral hemisphere	General clinical features of brain tumors (e.g., epileptic seizures)	MRI: T1 hypointense T2 hyperintense Inhomogenous, perifocal edema In contrast to glioblastoma, no necrosis CT: positive mass effect, hypointense, variable contrast enhancement	Tumor debulking through surgery Percutaneous radiotherapy/chemotherapy	5 - year survival rate: ∼ 23%
IV	Glioblastoma	65–75 years of age Most common primary nervous system cancer	White matter of the cerebral hemisphere (possibly bilateral = butterfly glioma)	General clinical features of brain tumors (e.g., epileptic seizure) Apoplectic glioma: mimics an intracranial hemorrhage; symptoms of raised ICP	MRI: T1 mixed T2 hyperintense Irregular, enhancing margins with a necrotic core Perifocal edema May also have multifocal enhancements Midline shift CT: Garland-like contrast enhancement, significant mass effect	Surgical resection Palliative percutaneous radiotherapy/chemotherapy (temozolomide) Glucocorticoids (in intracranial pressure)	Unfavorable Life expectancy of 6 months to 1 year
Variable	Brainstem glioma	3–10 years of age Comprise 15% of all childhood brain tumors	Brainstem	Vomiting Ataxia Cranial nerve deficits Hydrocephalus	MRI: T2 hyperintense, no contrast enhancement	Surgical resection is often difficult	Poor, especially in diffuse pontine gliomas Median survival: ∼ 10 months

Astrocytomas nearly always stain positive for glial fibrillary acidic protein (GFAP).

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