Congenital absence of the vagina is a congenital malformation, characterized by normal female karyotype, normal growth and development of secondary sexual characteristics, normal external genitalia, absence of the vagina, normal development of the uterus (only with bilobed remnants), small fallopian tubes, normal development and function of the ovaries, and Rokitansky-Kustner-Hauser syndrome patients with the most common features.
Patients with testicular feminization (androgen insensitivity syndrome) are relatively rare. A few are true hermaphrodites or those with incomplete gonadal development. Congenital absence of the vagina is the result of incomplete development of the mesonephric duct during embryogenesis and requires vaginoplasty. During the process of human embryonic development, regardless of male or female, there are two pairs of longitudinal tubes, the mesonephric duct and the mesonephric ductal side. The longitudinal part of the mesonephric ductal side develops into the fallopian tube; the transverse part of the middle segment develops into the fundus and body of the uterus; the longitudinal part of the distal segment develops into the cervix and upper segment of the vagina. The most distal part of the two sides of the mesonephric ductal side merges and extends to the back of the urogenital sinus, forming a mesonephric nodule at the third month of embryogenesis. The two mesonephric nodules connect to form the lower segment of the vagina. Congenital absence of the vagina is due to abnormal development of the upper segment of the vagina, that is, the two sides of the mesonephric ductal side do not extend to the distal end after merging.