title: Synchronous rosette-forming glioneuronal tumor and diffuse astrocytoma with molecular characterization: a case report.
abstract: Rosette-forming glioneuronal tumor (WHO grade I) is a rare neoplasm primarily arising in young adults that is characterized by distinctive neurocytic rosette formation, a spindled glial component resembling pilocytic astrocytoma, and a high incidence of PIK3CA mutation. Low-grade diffuse astrocytoma (WHO grade II), on the other hand, is far more common and is characterized by a high incidence of IDH mutation. Here we report a patient with simultaneous presentation of a midbrain-cerebellar rosetteforming glioneuronal tumor and a cerebral diffuse astrocytoma. Molecular characterization of both tumors confirmed characteristic, mutually exclusive, distinct signatures, with the rosette-forming glioneuronal tumor exhibiting a previously unreported novel PIK3CA gene mutation.
authors.forename: David
authors.initials: D
authors.lastname: Cachia
authors.forename: Marta Penas
authors.initials: MP
authors.lastname: Prado
authors.forename: Brett
authors.initials: B
authors.lastname: Theeler
authors.forename: Jackson
authors.initials: J
authors.lastname: Hamilton
authors.forename: Ian
authors.initials: I
authors.lastname: McCutcheon
authors.forename: Gregory N
authors.initials: GN
authors.lastname: Fuller
mesh_terms: D000328:Adult; D001254:Astrocytoma / Q000175:diagnosis / Q000473:pathology*; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D001932:Brain Neoplasms / Q000175:diagnosis / Q000473:pathology*; D002551:Cerebral Ventricle Neoplasms / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D020546:Fourth Ventricle / Q000473:pathology; D018303:Ganglioglioma / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D018302:Neoplasms, Neuroepithelial / Q000473:pathology; D012397:Rosette Formation