• Clinical science

Astrocytoma

Summary

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 malignant primary 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.

Differential diagnosis of astrocytomas

WHO grade

Type Age Location Symptoms Imaging Treatment Prognosis
I
  • Children and young adults (< 20 years)
  • 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
  • Most frequently children (< 10 years)
  • 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
  • 20–40 years of age
  • Cerebral hemisphere
  • 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
  • 30–50 years of age
  • Cerebral hemisphere
  • MRI:
  • CT: positive mass effect, hypointense, variable contrast enhancement
  • 5 - year survival rate: ∼ 23%
IV
  • 65–75 years of age
  • Most common malignant primary nervous system cancer
  • 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
  • Unfavorable
  • Life expectancy of 6 months to 1 year
Variable
  • 3–10 years of age
  • Comprise 15% of all childhood brain tumors
  • MRI: T2 hyperintense, no contrast enhancement
  • Surgical resection is often difficult

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

References:[1][2][3][4][5][6][7][8][9][10][11][12][13][14]