Congenital left posterolateral diaphragmatic hernia with previously normal chest x-ray.

Three patients who presented with left congenital posterolateral diaphragmatic hernia at the ages of six months, two years and six years and who had a normal chest x-ray earlier in life are reported. In two children the late onset of symptoms and previously normal radiographic appearance might be explained by the spleen acting as a plug in the diaphragmatic defect. A normal chest x-ray in early infancy does not exclude the diagnosis of congenital posterolateral diaphragmatic hernia.