Fibrosarcoma of bone is a rare malignant tumor accounting for less than 5% of all primary malignant bone neoplasms. There is very limited knowledge regarding the molecular genetics of this tumor, and there are no cytogenetic data available. In the present study, a fibrosarcoma deriving from the left iliac bone of a 10-year-old girl was characterized using cytogenetics, fluorescence in situ hybridization (FISH), and whole genome tiling resolution array comparative genomic hybridization (CGH). Cytogenetic and FISH analyses revealed a ring chromosome 6 as the sole acquired aberration, a finding corroborated by array CGH. The ring formation, however, did not result in any gain of genetic material. Nor did the breakpoints in 6p25 and 6q14 seem to affect any known gene loci in such a way that the ring formation could have resulted in the creation of a fusion gene or in the exchange of regulatory sequences. Thus, a reasonable interpretation of the pathogenetic significance of the ring formation would be that it resulted in the loss of one or more putative tumor suppressor gene loci distal to the two breakpoints.