Endocervical adenocarcinoma in situ of tubal type and its relation to atypical tubal metaplasia.

Endocervical adenocarcinoma in situ (AIS) is currently classified as having endocervical, endometrioid, or intestinal differentiation or admixtures of these patterns. Tubal metaplasia (TM) of endocervical mucosa has been considered a benign lesion that may be confused with AIS but has no malignant potential. In recent years, an increasing number of cases in which TM not only coexists with AIS, but also possesses atypia with transitions between ordinary TM, atypical TM, and AIS with residual tubal morphology have been reviewed by the authors, largely in consultation material. The clinical and pathologic features of 11 cases showing tubal and other types of AIS arising in a background of TM are reported. It cannot be assumed that all ciliated tubal epithelium in the cervix is benign and possesses no premalignant potential. The relationship of atypical TM (dysplasia) to tubal-type AIS must be defined, and the latter pattern should be added to the known types of differentiation of cervical AIS.