Cytogenetic instability, predominantly involving chromosome 1, is characteristic of elastofibroma.

Elastofibroma, an unusual pseudotumor composed of excessive collagen and abnormal elastic fibers, has rarely been subjected to cytogenetic analysis. Only two cases have been previously defined, both of which demonstrated nonclonal abnormalities. In the present study, three cases of elastofibroma were cytogenetically analyzed. Abnormalities of the short arm of chromosome 1 were seen in all three cases (either clonally or as the most frequently involved region among nonclonal aberrations). In addition, a translocation involving chromosomes 8 and 12 was detected as a clonal rearrangement in one of the three cases. The observation of clonal abnormalities in elastofibroma suggests that this lesion may represent a neoplastic rather than a reactive process.