Snapshot A 16-year old girl comes to her pediatrician with the complaint that she "has never had a menstrual period." Her past medical history is unremarkable, and she has developed along her growth curves. Her mother and sister both had their first mesntrual periods at 12 years of age. Her exam reveals normal female external genitalia and normal breast and pubic hair development. Introduction Congenital absence of a uterus and upper vagina also described as Müllerian aplasia or Müllerian agenesis the most common cause of vaginal agenesis The most common single diagnosis cause of primary amenorrhea (15% of cases) Chromosomally: 46, XX with intact ovaries Hormonally normal Presentation Symptoms primary amenorrhea normal development of secondary sexual characteristics, including thelarche and adrenarche Physical exam complete or partial absence of the cervix, uterus, vagina Imaging ultrasound supports diagnosis Differential Diagnosis Complete Androgen Insensitivity Syndrome (AIS) In AIS, differences include: genotype XY decreased pubic and axillary hair increased height presence of intra-abdominal testicles Treatment With early diagnosis, management involves the use of successive dilators as the patient grows Treatment often involves extensive psychological counseling Even with dilation, surgical intervention is often required for the creation of a neo-vagina