title: Glioneuronal phenotype in a diencephalic pilomyxoid astrocytoma.
abstract: We report the presence of divergent populations of cells in a hypothalamic/chiasmatic pilomyxoid astrocytoma of an 11-month-old male, exhibiting differential immunohistochemical localizations for glial fibrillary acidic protein (GFAP) and synaptophysin. The tumor cells were negative for Neu-N and neurofilament protein. Ultrastructurally, the tumor comprised 2 cell types, one with features attributable to a neuronal phenotype alongside cells exhibiting an overt astroglial phenotype. This composite organization was confirmed by confocal microscopy, which revealed 2 distinct, albeit tightly interwoven, populations of GFAP and synaptophysin-labeled tumor cells. Our results indicate that a subset of the so-called pilomyxoid astrocytomas of the hypothalamic/chiasmatic region may represent phenotypically mixed glioneuronal neoplasms distinct from the pilocytic astrocytomas.
authors.affiliation: Department of Pathology and Laboratory Medicine, Drexel University College of Medicine and St. Christopher's Hospital for Children, Erie Avenue at Front Street, Philadelphia, PA 19134, USA. JD37@Drexel.edu
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: de Chadarévian
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Halligan
authors.forename: Goutham
authors.initials: G
authors.lastname: Reddy
authors.forename: Louise
authors.initials: L
authors.lastname: Bertrand
authors.forename: Judy M
authors.initials: JM
authors.lastname: Pascasio
authors.forename: Eric N
authors.initials: EN
authors.lastname: Faerber
authors.forename: Christos D
authors.initials: CD
authors.lastname: Katsetos
mesh_terms: D001253:Astrocytes / Q000648:ultrastructure; D001254:Astrocytoma / Q000737:chemistry / Q000473:pathology*; D001932:Brain Neoplasms / Q000737:chemistry / Q000473:pathology*; D018303:Ganglioglioma / Q000737:chemistry / Q000473:pathology*; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006801:Humans; D007031:Hypothalamus / Q000473:pathology*; D007124:Immunoenzyme Techniques; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D009474:Neurons / Q000648:ultrastructure; D010641:Phenotype; D016708:Synaptophysin / Q000032:analysis
chemical_list: D005904:Glial Fibrillary Acidic Protein; D016708:Synaptophysin