Trisomies 8 and 20 characterize a subgroup of benign fibrous lesions arising in both soft tissue and bone

Trisomy 8 and trisomy 20 are nonrandom aberrations in desmoid tumors, The p resence of these trisomies in related benign fibrous lesions of bone has no t been previously addressed. In this study, 22 specimens from 19 patients d iagnosed with desmoid tumor, desmoplastic fibroma, periosteal desmoid tumor , osteofibrous dysplasia, or fibrous dysplasia were examined by cytogenetic analysis of short-term cultures and bi-color fluorescence in situ hybridiz ation of cytological touch preparations or paraffin-embedded tissue with ce ntromeric probes for chromosomes 8 and 20. Trisomy 8 and trisomy 20 were de tected by molecular cytogenetic methodologies In 15 specimens, Including 10 primary bone lesions. Traditional cytogenetic analysis revealed trisomy 8 in two cases of osteofibrous dysplasia. Our findings demonstrate that triso my 8 and trisomy 20 are also nonrandom aberrations in histologically simila r, but clinically distinct, benign fibrous lesions of bone.