The effects of endocervical canal topography, tubal metaplasia, and high canal sampling on the cytologic presentation of nonneoplastic endocervical cells.

Use of new endocervical cytologic sampling devices has correlated with increased numbers of cases showing endocervical "atypia." To ascertain the potential causes, a cytologic and histologic correlative study of the normal endocervical canal was undertaken. Hysterectomy specimens from 25 patients with no history of cervical disease were used. The anterior and posterior endocervical canals were divided into three equal sections. Each of the sections of the anterior canal were sampled cytologically, with the corresponding posterior canal processed for histology. Endocervical gland number, depth, and cellular crowding were most pronounced in the middle third of the canal. Tubal metaplasia (present in 100% of cases) was most prominent in the upper third. The most cellular cytologic samples were obtained from the middle third. "Atypical" endocervical groups were most commonly identified in the upper third. The normal topography of the endocervical canal, with sampling of the upper regions by newly utilized devices, may account for the increase in samples showing cytologic patterns that mimic endocervical neoplasia.