Pleomorphic xanthoastrocytoma: the birth of a diagnosis and a concept.

This review deals with one of the newly adopted entities in the second edition of the histologic typing of CNS tumours by the World Health Organization: pleomorphic xanthoastrocytoma and reviews the clinical features, gross and microscopic characteristics as well as the common and some of the unusual variants of this tumor. The steps and events leading to the recognition of the basic character of this neoplasm and its designation as an independent entity are recollected and a few characteristic MRI scans and photomicrographs of pleomorphic xanthoastrocytomas are provided.