Involvement of chromosomes 12 and 14 in the cutaneous stage of mycosis fungoides: cytogenetic evidence for a multistep pathogenesis of the disease.

Cytogenetic studies were performed on the cells of bone marrow, peripheral blood, and skin tumor biopsies from a patient with mycosis fungoides at an early stage. Chromosome abnormalities were detected in 100% of the cells harvested from the cutaneous specimen, whereas the cells of the bone marrow and blood were karyotypically normal. Three related clones, showing increasing cytogenetic complexity, were found. Chromosome #12 was abnormal in all metaphases, and an abnormal 14q chromosome was present in a minority of cells belonging to the most complex emerging subclone. These data, along with the findings of important signs of chromosome imbalance, suggest a polyphasic evolution of this chronic T lymphoproliferative disease.