Cytological changes associated with tubo-endometrioid metaplasia of the uterine cervix

Two women who had undergone previous cervical surgery for the treatment of glandular intraepithelial neoplasia (GIN) and cervical intraepithelial neoplasia (CIN), were found to have severely dyskaryotic cells of glandular and metaplastic type in follow-up cervical smears. A third patient was found to have similar abnormal cells in a routine screening smear. All of the patients were subjected to either hysterectomy or cervical conization and in all cases histological examination showed tubo-endometrioid glands in the endocervix, well away from the uterine isthmus, with no associated endometrial stromal tissue. All of the cervical smears were reviewed and cytological features that facilitate the distinction between tubo-endometrioid metaplasia and squamous or glandular dyskaryosis were identified. These features include the smaller size of affected cells, more marked nuclear hyperchromasia, inconspicuous nucleoli, the formation of glandular structures, the lack of discrete squamous dyskaryosis and the absence of the typical 'feathering' noted with GIN. The possibility of tubo-endometrioid metaplasia should be considered when atypical glandular or metaplastic cells are noted in cervical smears, particularly, but not exclusively, in women who have been treated for CIN or GIN. In the presence of these changes clinicians should rebiopsy the cervix before embarking on further unnecessary surgery which may adversely affect fertility and pregnancy, particularly in younger patients.