Lineage-restricted chromosome translocation in a benign fibrous tumor of the breast

We describe a clonal chromosome rearrangement, t(4;14)(q24-25;q24.3), in a benign fibrous tumor of the breast. This is the first reported cytogenetic analysis of a fibrous tumor of the breast and the first evidence for clonality in these lesions. A combined immunohistochemical/cytogenetic study demonstrated that cells with the clonal translocation were mesenchymal. Epithelial cells, in contrast, had normal chromosomes.