Congenital Aplasia of the Uterine-Vaginal Segment in Dogs

Müllerian duct abnormalities consist of a set of structural malformations that include diverse situations of agenesis or aplasia, which may evolve according to three distinct patterns: a failure of the paramesonephric ducts (Müllerian ducts) to develop in the whole or in part (uterus unicornis and segmental aplasia of uterine horn, respectively), the failure of caudal part of the paramesonephric ducts to the fuse and to form one single lumen (leading to situations such as uterus didelphus and the cranial vagina septation) and the failure of the fused caudal paramesonephric ducts to fuse with the urogenital sinus with consequent absence of anatomic continuity between the cranial vagina and the vestibule (originating an imperforate hymen or the vaginal stenosis).