Proliferative lesions of the bone surface, such as subungual (Dupuytren) exostosis and bizarre parosteal osteochondromatous proliferation (BPOP, Nora lesion) are currently classified as reactive, proliferative processes that mimic primary neoplasms of bone.
Cytogenetic analysis was performed on 3 subungual exostoses of the great toe and 2 BPOP lesions of the radius and ulna.
A balanced translocation t(X;6) was identified in all cases of subungual exostoses. The chromosomal rearrangements observed in 1 case of BPOP differed from those seen in subungual exostosis.
The presence of chromosomal abnormalities in subungual exostosis and BPOP suggests that these lesions are neoplastic, with a different molecular pathogenesis, and that each is a distinct clinicopathologic entity.