- Congenital anomaly with defective fusion of the posterolateral pleuroperitoneal layers.
- 85–90% on the left, 10–15% on the right. Usually unilateral lying posteriorly within the chest.
- Hernia may contain fat or intra-abdominal organs.
- In neonates the hernia may be large and present in utero. This is associated with high mortality secondary to pulmonary hypoplasia (60%).
- Small hernias are often asymptomatic containing a small amount of fat only. They have a reported incidence up to 6% in adults.
- Large hernias are diagnosed antenatally with US.
- Neonates may present with respiratory distress early in life. Early corrective surgery is recommended.
- Smaller hernias are usually asymptomatic with incidental diagnosis made on a routine CXR.
- Occasionally solid organs can be trapped within the chest compromising the vascular supply. Patients report localised pains and associated organ-related symptoms, e.g. change in bowel habit.
- CXR – a well-defined, dome-shaped soft tissue opacity is seen midway betweenthespine andthe lateralchestwall.Thismay ‘comeandgo’.There may be loops of bowel or gas-filled stomach within the area. The ipsilateral lung may be smaller with crowding of the bronchovascular markings and occasionally mediastinal shift. AnNGtubemay lie curled in the chest.
- CT – small hernia are difficult to demonstrate even on CT. Careful inspection for a fatty or soft tissue mass breaching the normal smooth contour of the posterior diaphragm.
- In neonates, both congenital cystic adenomatoid malformation (CCAM) and pulmonary sequestration may have similar features. Cross-sectional imaging with CT _ MRI utilising 2D reformats is often very helpful.
- In adults, the plain film findings mimic pulmonary neoplasms, bronchogenic cysts and infections (_ cavitation).
- Large hernias in neonates require early surgical repair. They may also require respiratory support.
- In adults no active management is required in asymptomatic individuals.