[A colonic structure in the placenta: a simple teratoma coaetans or ectopic differentiation?].

A cylindrical structure which was closed on either side and covered by the amnion was found in a placenta. Histological examination showed well differentiated wall of large intestine with sympathetic plexus. Several hypothesis are discussed: teratoma, fetus acardiacus amorphus, anomalous differentiation of the yolk sac.