9424/3 Pleomorphic xanthoastrocytoma


Definitions

Tumours of the central nervous system
ICD-O-3 topography code: C70, C71 and C72
ICD10: C71
           

Pleomorphic xanthoastrocytoma (PXA) is a rare and distinct type of astrocytoma, which occurs predominantly in children and young adults. The tumor has a typical superficial location in the cerebral hemispheres with involvement of the adjacent meninges and is frequently cystic. Characteristic histological features include large pleomorphic and frequently multinucleated cells, with xanthomatous features, embedded in a reticulin network, with scattered pale or brightly eosinophilic granular bodies. Despite the alarming histological appearance, PXA has a relatively favourable prognosis as compared to diffusely infiltrative astrocytomas and largely behaves as a grade II tumor, the grade assigned to it by the WHO. 1
 
Louis DN, Ohgaki H, Wiestler OD, Cavenee WK (Eds.)
WHO Classification of Tumours of the Central Nervous System.
4th Edition
International Agency for Research on Cancer: Lyon 2007




Tumors displaying significant mitotic activity and/or areas of necrosis are designated by the WHO as "PXA with anaplastic features" and may behave in a more aggressive fashion with an increased risk of early recurrence
2
Click to access Pubmed
Giannini C, Scheithauer BW, Burger PC, Brat DJ, Wollan PC, Lach B, O'Neill BP (1999)
Pleomorphic xanthoastrocytoma: what do we really know about it?
Cancer 85: 2033-45



. Definite grading criteria for WHO grade III tumors however have yet to be established.