title: Clinicopathologic features of pediatric oligodendrogliomas: a series of 50 patients.
abstract: Oligodendrogliomas are an important adult form of diffuse gliomas with a distinctive clinical and genetic profile. Histologically similar tumors occurring rarely in children are incompletely characterized. We studied 50 patients with oligodendrogliomas (median age at diagnosis 8 y, range 7 mo to 20 y). Tumors resembling dysembryoplastic neuroepithelial tumors or pilocytic astrocytomas or those having a "mixed" histology were excluded. Tumors at first diagnosis were low grade (n=38) or anaplastic (n=12). Histologic features included uniform round cells with perinuclear halos (100%), secondary structures (predominantly perineuronal satellitosis) (90%), calcifications (46%), and microcysts (44%). Sequential surgical specimens were obtained in 8 low-grade oligodendroglioma patients, with only 1 progressing to anaplasia. Studies for 1p19q performed in 40 cases demonstrated intact 1p19q loci in 29 (73%), 1p19q codeletion in 10 (25%), and 1p deletion with intact 19q in 1 (2%). Except for 2 young patients (3 and 11 y of age), patients with 1p19q codeletion were older than 16 years at diagnosis. Mutant IDH1 (R132H) protein immunohistochemistry was positive in 4 (of 22) (18%) cases, 3 of which also had 1p19q codeletion, whereas 1p19q status was not available on the fourth case. There was a nonsignificant trend for worse overall survival in grade III tumors, but no significant association with age, extent of resection, or 1p19q status. In summary, oligodendrogliomas with classic histology occur in the pediatric population but lack 1p19q codeletion and IDH1 (R132H) mutations in most instances. They are predominantly low grade, recur/clinically progress in a subset, but demonstrate a relatively low frequency of histologic progression.
authors.affiliation: Departments of *Pathology §Radiology †The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, MD Departments of ‡Pathology ¶Neurological Surgery, University of California San Francisco School of Medicine, San Francisco, CA ∥Hospital Pathology Associates, Minneapolis, St Paul, MN #University of Arizona, College of Medicine, Phoenix, AZ.
authors.forename: Fausto J
authors.initials: FJ
authors.lastname: Rodriguez
authors.forename: Tarik
authors.initials: T
authors.lastname: Tihan
authors.forename: Doris
authors.initials: D
authors.lastname: Lin
authors.forename: William
authors.initials: W
authors.lastname: McDonald
authors.forename: Janice
authors.initials: J
authors.lastname: Nigro
authors.forename: Burt
authors.initials: B
authors.lastname: Feuerstein
authors.forename: Sadhana
authors.initials: S
authors.lastname: Jackson
authors.forename: Kenneth
authors.initials: K
authors.lastname: Cohen
authors.forename: Peter C
authors.initials: PC
authors.lastname: Burger
mesh_terms: D000293:Adolescent; D001932:Brain Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D002872:Chromosome Deletion; D002878:Chromosomes, Human, Pair 1; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D053208:Kaplan-Meier Estimate; D008297:Male; D009837:Oligodendroglioma / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D016133:Polymerase Chain Reaction; D055815:Young Adult