The cobweb syndrome: first trimester sonographic diagnosis of multiple amniotic bands confirmed by fetoscopy and pathological examination.

Amniotic band syndrome is a well described clinical entity presenting with deformities of the limbs, thorax, craniofacial skeleton, soft tissues and umbilical cord, but it still lacks a precise definition and a coherent hypothesis for its pathogenesis. We report on a case of first trimester diagnosis of amniotic band syndrome by sonography and fetoscopy. This revealed multiple abnormalities including facial cleft, brain and limb deformities; the appearance of the amniotic cavity was that of a cobweb containing the fetus. Post-mortem examination and histopathological studies confirmed the diagnosis of amniotic band syndrome. These results may enhance the knowledge of its natural course. In addition, based on histological and newly identified ultrastructural features, we present a hypothesis which could help to explain the aetiopathogenesis of the amniotic band syndrome.