[Trisomy 18 and prune belly syndrome].

Ultrasonic examination in a thirty five years old woman about to undergo midtrimester amniocentesis suggested an intra abdominal fetal mass. The mass was a grossly distended urinary bladder. The pregnancy was terminated at 20 weeks. Necropsy was confirmative for a prune-belly syndrome. Chromosomal analysis demonstrated a 47 XY + 18 karyotype.