Vaginal Agenesis and the Embryology of Vaginal Epithelium

Abstract

EDITORIAL COMMENT: We have accepted this paper for publication because we hope that readers will enjoy the discussion about the embryology of the vagina. Although the hymen has stratified squamous epithelium on both superior and inferior surfaces there are reported cases (A) of a transverse vaginal septum above the level of the hymen where the superior surface was covered by columnar epithelium and the inferior surface by squamous epithelium (figure A, 1 and 2). One interpretation of this finding is that the columnar epithelium was derived from Mullerian duct tissue and thus, that the squamous epithelium of the vagina arises by replacing Mullerian duct tissue. There is controversy regarding whether this second epithelium arises from endoderm of the urogenital sinus, mesoderm of the Wolffian ducts or ectoderm of the cloacal membrane (B). Recently a case of double uterus with 1 side having a blind vagina was seen in the University Department at the Mercy Hospital for Women. With this article in mind biopsies were taken from the vaginal walls in the side that had the haematocolpos. The biopsies showed columnar epithelium similar to endocervical epithelium. The editorial committee referred this article for opinion from anatomists and embryologists at the University of Melbourne, Department of Anatomy and Cell Biology and their comments are included as an addendum to this paper. Some of the arguments presented are not easy to follow and the editor considers that a convincing case is yet to be made to reverse the traditional teaching on the embryology of the vagina. Stewart AD. Cryptomenorrhoea due to a transverse vaginal septum. Aust N Z J Obstet Gynaecol 1968; 8: 45–48. Deppisch LM. Transverse vaginal septum. Histologic and embryologic considerations. Obstet Gynecol 1972; 193–198. Summary: A review has been made of 29 cases of vaginal agenesis treated by the Sheares technique of vaginoplasty at the Royal Women's Hospital, Melbourne since 1976. Spontaneous epithelialization of the neovagina is rapid providing the newly created space is kept patent by regular dilatation. The process is usually complete by the 10th to 12th postoperative week. A review of the embryology of vaginal epithelium suggests that it is entirely of urogenital sinus origin. In cases of vaginal reconstruction where no grafting technique is employed it seems likely that epithelial rests are responsible for the rapid epithelialization that occurs.