Pleomorphic xanthoastrocytoma

Abstract

The pleomorphic xanthoastrocytoma (PXA) is a rare tumor type of astrocytic origin that was fi rst described as a distinct neoplastic entity by Kepes and coauthors in 1979 [16]. The PXA was added as a separate diagnosis to the 1993 World Health Organization (WHO) classification of central nervous system tumors [17]. Prior to the advent of immunostaining, PXAs were thought to represent neoplasms of mesenchymal origin [15]. This was due to the abundant reticulin network often found in these tumors, and also due to the resemblance between the tumor's lipidized neoplastic glial cells and foamy histiocytes, or xanthoma cells. This resemblance explains why PXA had been previously labeled as xanthomas or xanthosarcomas [14]. The PXA superficial location with intense desmoplastic reaction causing adherence to adjacent dura no doubt contributed to the confusion concerning the origin of this neoplasm. These tumors were also occasionally designed giant-cell glioblastomas due to the presence of aggressive histological features, including bizarre multinucleated giant cells. In contrast to mesenchymal tumor and giant-cell glioblastomas, PXAs are associated with an intermediate clinical course. Their pathological recognition therefore has important prognostic implications. © 2010 Springer-Verlag Berlin Heidelberg.