Anaplastic pleomorphic xanthoastrocytomas are a more aggressive and less common version of pleomorphic xanthoastrocytoma (PXA).
In the current (2016) WHO classification of CNS tumours, they are considered WHO grade III lesions (whereas pleomorphic xanthoastrocytomas are WHO grade II tumours) 1.
As clinical and imaging features are essentially the same as lower grade tumours, they are not repeated here but rather discussed as part of the article on pleomorphic xanthoastrocytoma.
Anaplastic pleomorphic xanthoastrocytomas are defined as a tumour consistent with a pleomorphic xanthoastrocytoma but with an increased mitotic rate of >5 mitoses per 10 high-power fields 1. Otherwise, histologically they are very similar with lower grade tumours, however, necrosis and vascular proliferation are more common 1. They can be difficult to distinguish from epithelioid glioblastomas 1.
Treatment and prognosis
Anaplastic pleomorphic xanthoastrocytomas have a substantially worse prognosis; 40-50% 5-year-survival compared to ~90% 5-year-survival for pleomorphic xanthoastrocytomas 1.
- 1. Louis DN, Ohgaki H, Wiestler OD, Cavenee WK "WHO Classification of Tumours of the Central Nervous System. 4th Edition Revised" ISBN: 9789283244929
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