CHROMOSOME-ABERRATIONS IN CHOROID-PLEXUS PAPILLOMAS

Karyotypic data on choroid plexus papillomas are scarce and, to date, have revealed no consistent aberrations. We karyotyped a choroid plexu s papilloma which was characterized by a stemline of 52, XX, + 7, + 11 , + 12, + 12, + 15, + 18. Additional copies of chromosomes 16, 17, and 20 were also observed in a significant proportion of the metaphase ce lls analyzed. Based upon this index case, we retrospectively analyzed eight additional choroid plexus papillomas by fluorescence in situ hyb ridization by using pericentromeric probes to chromosomes 7, 11, 12, 1 5, 16, 17, 18, and 20. Extra hybridization signals were observed in fi ve of the eight cases examined. All five cases had extra signals with the chromosome 7 probe, four cases had extra signals with the chromoso me 12 probe, and three cases had extra signals with the chromosome 15, 17, and 18 probes. The overall DNA content of these same cases (as de termined by image analysis) suggests that gains of additional chromoso mes other than those examined may be present. (C) 1994 Wiley-Liss, Inc .