Supernumerary ring chromosome in a Bednar tumor (pigmented dermatofibrosarcoma protuberans) is composed of interspersed sequences from chromosomes 17 and 22: A fluorescence in situ hybridization and comparative genomic hybridization analysis

Cytogenetic analysis of Bednar tumor (pigmented dermatofibrosarcoma protuberans) has not been reported previously. Here, we report the identification of a supernumerary ring chromosome in a Bednar tumor by chromosome painting with fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH). Chromosome painting with FISH demonstrated that the supernumerary ring chromosome was composed of discontinuous, interwoven sequences from chromosomes 17 and 22. Amplification of chromosomes 17 and 22 sequences was confirmed by CGH. These results indicate that Bednar tumor and dermatofibrosarcoma protuberans are characterized by the same chromosomal features. To our knowledge, this is the first report that the ring chromosome in Bednar tumor is composed of amplified material from chromosomes 17 and 22. © 2001 Wiley‐Liss, Inc.