Tamoxifen-associated postmenopausal adenomyosis exhibits stromal fibrosis,glandular dilatation and epithelial metaplasias

Aims: Adenomyosis is relatively rare in postmenopausal women but recent rep orts have described its occurrence in this age group in patients taking tam oxifen. This study describes the pathology of nine cases of adenomyosis in postmenopausal women who were taking this medication. Methods and results: The pathology of the nine tamoxifen-associated cases w as compared to five cases of postmenopausal adenomyosis not associated with tamoxifen. Morphological features present within adenomyosis more often in those taking tamoxifen were cystic dilatation of glands (which sometimes r esulted in grossly visible intramural cystic lesions), fibrosis of the stro ma and various epithelial metaplasias. The proliferative activity within th e adenomyosis, as determined by MIB1 staining, was higher in the tamoxifen group. Conclusions: The study supports an association between tamoxifen therapy an d the presence of adenomyosis in postmenopausal women. The aforementioned m orphological features are characteristic of polypoid and nonpolypoid surfac e endometrium associated with tamoxifen and their occurrence within the ade nomyosis is likely to represent extension of the surface epithelial changes . Adenomyosis may be more common than is generally realized in women taking tamoxifen and may account for postmenopausal bleeding in these patients.