The pleomorphic xanthoastrocytoma and its differential diagnosis: A study of five cases

__Abstract__ Five brain tumors with the histopathologic features of pleomorphic xanthoastrocytomas (PXAs) are presented. Computed tomography scans showed a remarkable homology. Two cases had atypical localizations for a PXA, while one 46-year-old patient did not conform to the normal age distribution of this tumor. Nevertheless, in these cases, the histopathology was always characteristic for PXA, a remarkable pleomorphism, in addition to simultaneous expression of glial fibrillary acidic protein and histiocytic markers in the various tumor cells. In one of the presented tumors, however, clusters of neoplastic neuronal cells were also found. In this particular case, differential diagnostic criteria to distinguish between a PXA and a desmoplastic infantile ganglioglioma are lacking

Presenile Alzheimer dementia characterized by amyloid angiopathy and large amyloid core type senile plaques in the APP 692 Ala => Gly mutation

Mutations at codons 717 and 670/671 in the amyloid precursor protein (APP) are rare genetic causes of familial Alzheimer's disease (AD). A mutation at codon 693 of APP has also been described as the genetic defect in hereditary cerebral hemorrhage with amyloidosis of the Dutch type (HCHWA-D). We have reported a APP692Ala-->Gly (Flemish) mutation as a cause of intracerebral hemorrhage and presenile dementia diagnosed as probable AD in a Dutch family. We now describe the post-mortem examination of two demented patients with the APP692 mutation. The neuropathological findings support the diagnosis of AD. Leptomeningial and parenchymal vessels showed extensive deposition of A