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anaplastic astrocytoma (grade 3)
Astrocytoma with anaplasia (Grade 3).
Pathology:
1) increased cellularity
2) nuclear atypia
3) mitoses
4) tend to progress to glioblastoma
Genetics:
- chromosome 9p loss in 50% of anaplastic astrocytomas & GBMs primarily affecting CDKN2A gene
- chromosome 13q loss in 1/3 - 1/2 of high grade astrocytomas RB gene inactivated in 20% of anaplastic astrocytomas, 35% GBMs
- chromosome 12q13-14 amplification in 15% malignant gliomas including gene for CDK4
- allelic loss on chromosome 19q in up to 40% of anaplastic astrocytomas and GBMs
- diminished or absent expression of PHF3
Radiology:
1) magnetic resonance imaging (MRI)
2) computed tomography (CT)
3) higher grade astrocytomas show contrast enhancement
Management:
1) radiation
a) prolongs survival
b) 5000-6500 cGy
c) administered in multiple fractions to an area around the tumor
d) radiation necrosis may produce clinical picture indistinguishable from recurrent high-grade tumor
2) dexamethasone
a) administered with radiation therapy
b) tapered to lowest dose after radiation
3) chemotherapy (BCNU, CCNU) combined with radiation
- treatment of choice [1] (marginally effective [2])
4) surgery
a) surgical excision is not possible because anaplastic astrocytomas infiltrate adjacent brain tissue
b) may be useful to reduce mass effect
c) stereotaxic radiosurgery with gamma knife
1] potential for tumor abalation
2] useful for tumors < 3 cm in diameter
5) prognosis: 50% survival of 12 months (with radiation)
Interactions
disease interactions
General
astrocytoma (astrocytic neoplasm)
malignant glioma
References
- Medical Knowledge Self Assessment Program (MKSAP) 11, American
College of Physicians, Philadelphia 1998
- Harrison's Online, Chapter 370, McGraw-Hill, 2002