Three unusual cases of large anterolateral congenital diaphragmatic he
rnia are described with emphasis on its embryogenesis. This type of di
aphragmatic defect is rare and underemphasized. Its clinical spectrum
ranges from the asymptomatic case to those with acute respiratory dist
ress. It may present itself as a solitary defect or as part of a more
complex association such as the thoracoabdominal syndrome. This defect
should be differentiated from Morgagni (and other anterior) diaphragm
atic hernias by its size and lateral extension and the presence of lef
t pulmonary hypoplasia. Treatment is by primary operative repair, and
prognosis depends on the presence and severity of associated malformat
ions.