Baboon cervical colposcopy, histology, and cytology.

Colposcopic cervical/vaginal examinations were performed on 10 healthy adult baboons. Five of the ten baboons had a "satisfactory" colposcopic cervical examination with columnar epithelium visible on the exocervix. However, only three of five with "satisfactory" colposcopic exams had large visible transformation zones. The colposcopic findings were confirmed by histologic study. Probable squamous metaplasia was seen in one of the four animals who underwent cervical biopsies. The histologic and cytologic similarities of the human and baboon cervical transformation zones were noted. Only the three animals with the large visible cervical transformation zones were considered suitable for colposcopic studies of the transformation zone. Thus only 30% of the baboons examined were considered suitable subjects for studies involving colposcopy. Screening colposcopic exams would be necessary to find this subpopulation of baboons with large transformation zones visible on the exocervix. The implications of this study relative to the use of baboons as an animal model for studies of intraepithelial neoplasia are discussed.