Clonal 6p21 rearrangement is restricted to the mesenchymal component of an endometrial polyp

Abstract Previous cytogenetic analyses revealed t(6;20)(p21;q 13) in two endometrial polyps. We karyotyped a large endometrial polyp in which 19 of 25 metaphase cells contained a t(1;6;4)(q21;p21;q 13). Subsequent combined immunohistochernical/cytogenetic analysis showed all aberrant metaphase cells to be of mesenchymal derivation, whereas epithelial cells from the polyp were diploid. These studies indicate that rearrangement of chromosome band 6p21 is a characteristic cytogenetic aberration in the stromal component of endometrial polyps.