Cone biopsy causes cervical endometriosis and tubo-endometrioid metaplasia.

Cervices from 42 hysterectomies performed from 1 to 91 months (mean 12.2) following conization were re-examined in order to assess the possible effects of post-traumatic regeneration on the endocervix. Twenty-nine (69%) showed a continuum of abnormalities in which the shared finding was the presence of tubo-endometrioid glands, accompanied in many cases by varying amounts of endometrial-type stroma. Thus, 18 post-conization cervices (43%) showed endometriosis, and a further 11 cases (26%) contained tubo-endometrioid glands without demonstrable endometrial-type stroma. These abnormalities were situated at the healed cone biopsy site, either superficially within the new transformation zone and/or within the cone biopsy scar. Post-conization cervical endometriosis occurred from 2 to 91 months (mean 17.8) and tubo-endometrioid metaplasia 2-24 months (mean 11.0) after the cone biopsy. It is concluded that cervical endometriosis and tubo-endometrioid metaplasia are common complications of conization, and that they represent aberrant differentiation following injury. The demonstration of endometriosis and tubo-endometrioid metaplasia in 69% of post-conization cervices has implications for the interpretation of cervical biopsies and smears from this group of women.