Polyploidy in atypical grade II choroid plexus papilloma of the posterior fossa.
Cytogenetic studies of choroid plexus tumors, particularly for atypical choroid plexus papillomas, have been rarely described. In the present report, the cytogenetic investigation of an atypical choroid plexus papilloma occurring at the posterior fossa of a 16-year-old male is described. Comparative genome hybridization analysis demonstrated gains of genetic material from almost all chromosomes. Chromosome losses involved 19p, regional losses at chromosome X and loss of chromosome Y. The presence of polyploid cells was confirmed by fluorescence in situ hybridization analysis with probes directed to centromeric regions. Furthermore, the microscopic analysis of cultures showed nuclear buds, nucleoplasmic bridges, and micronuclei in 23% of tumor cells suggesting the presence of complex chromosomal abnormalities. Previous cytogenetic studies on choroid plexus papillomas showed either normal, hypodiploid or hyperdiploid karyotypes. To the best of our knowledge, this is the first report of polyploidy in choroid plexus papilloma of intermediate malignancy grade. Although the mechanisms beneath such genome duplication remain to be elucidated, the observed abnormal nuclear shapes indicate constant restructuring of the tumor's genome and deserves further investigation.
Brassesco
María Sol
MS
Division of Pediatric Oncology, Department of Pediatrics, University of São Paulo, Av. Bandeirantes 3900, São Paulo, Brazil. marsol@rge.fmrp.usp.br
Valera
Elvis Terci
ET
Neder
Luciano
L
Castro-Gamero
Angel Mauricio
AM
Arruda
Darlene
D
Machado
Hélio Rubens
HR
Sakamoto-Hojo
Elza Tiemi
ET
Tone
Luiz Gonzaga
LG
D000293:Adolescent; D002467:Cell Nucleus / Q000235:genetics / Q000473:pathology; D053144:Cell Nucleus Shape; D002503:Centromere / Q000473:pathology; D002869:Chromosome Aberrations; D055028:Comparative Genomic Hybridization; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015192:Infratentorial Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D009367:Neoplasm Staging; D020288:Papilloma, Choroid Plexus / Q000235:genetics* / Q000473:pathology; D011123:Polyploidy