This 30 year-old primigravida mother has no particular history. At 33 weeks the fetus presents with 25 mm mass situated below the cord insertion and above the external female genitalia. The differential diagnosis was between omphalocele and extrophy of the bladder. The bladder could not be identified on 3 consecutive ultrasound examinations. The remainder of the ultrasound examination was unremarkable.

The volume of the mass varied with respiratory motion.

The mass in front of the thighs:

The umbilical arteries are not surrounding the bladder:

The 3D reconstruction of the mass:

The baby girl was delivered at 38 weeks with Apgar scores of 10 and 10 and operated 48 hours later for reconstruction of bladder extrophy.