Hymenal Atresia vs. Urethral Prolapse
Left picture: The cause of this interlabial mass, and therefore, the cause of the conspicuous external genitals in this girl is a mucocolpos in hymenal atresia. The backflow of mucus does not only lead to an enlargement of the vagina, but also to an increase in the uterus size, and thereby, to a visible and/or palpable abdominal tumor in the newborn, and to voiding disorders of bladder and anorectum. At the top of the protrusion there is a small drop of mucus on account of a minimal perforation. This speaks against a low vaginal atresia by a typically thick and rough membrane. Right picture: Here, the entrance to the vagina is for the most part still open. The correct diagnosis is an advanced and severe type of urethral prolapse.
Left picture: Newborn girl with an interlabial mass displacing the labia minora to the lateral side. Notice the traces of a yellow-white fluid at the posterior border of the mass. Right picture: 9.1-year-old girl with a dark-red interlabial mass. In the middle of the mass a depression is recognizable; the mass doesn´t lead to a significant enlargement and displacement of the introitus of the vagina.