Case of the Month - January
33-year-old woman. Generalized tonic-clonic seizures. Left hemihypoesthesia.
Anaplastic Astrocytoma (AA) (WHO III)
Definition
Diffuse infiltrating astrocytoma with focal or diffuse anaplasia and marked profilerative potential. MIB-1> 7-9%
Generalities
It evolves from a low-grade (diffuse) astrocytoma 75% of the time. They are 1/3 of astrocytomas and constitute 25% of gliomas. They progress to GBM in 2 years. They have a mortality between 2 to 3 years. AA is an infiltrative mass that predominantly involves the white matter
Location
Hemispheric in white matter, frequently frontal and temporal. In children frequently in bridge and thalamus. Less frequent in stem and spinal cord.
Histopathology
There is an increase in cellularity. There is marked mitotic activity, with cellular atypia. There is an increase in the nuclear / cytoplasmic rate. There is no necrosis or microvascular proliferation unlike GBM. Immunohistochemistry: PGAF +
Genetics
There is a high frequency of P53 mutation (more than 70%). Is it so altered some cell cycle regulatory genes. There is a p16 deletion, Rb alterations and a p19ARF deletion. There is loss of heterozygosity: chromosome 10q, 19q, 22q. There is a deletion of chromosome 6 (30%). For all this genetic variability, there is a worse prognosis compared to ODG.
References
Malignant Gliomas: Anaplasic Astrocytoma, Glioblastoma Multiforme, Gliosarcoma. Youmans Neurological Surgery. 2013, 7th Edition. edited by H. Richard Winn. Elsevier Medical.Pg 1327-1340
Burger PC, Scheithauer BW. Tumors of the Central Nervous System. AFIP Atlas of Tumor Pathology Series 4. Fascicle 7, 2007 The American Registry of Pathology. Pg 55-79
Louis DN, Ohgaki H, Wiestler OD, Cavenee WK, Burger PC, Jouvet A, Scheithauer BW, Kleihues P. The 2007 WHO Classification of Tumors of the Central Nervous System. Acta Neuropathol (2007) 114: 97–109
Greenberf MS. Oligodendroglioma. Handbook of Neurosurgery 2010, 7th Edition. Thieme
Sanai N, Berger MS. Brain Tumors: An Overview of Current Histopathologic Classifications. Youmans Neurologial Surgery. 2013, 7th Edition. edited by H. Richard Winn. Elsevier Medical.Pg 1318-1326