Intercostal lung herniation--the role of imaging

Abstract

Extrathoracic lung hernias can be congenital or acquired. Acquired hernias may be classified by etiology into traumatic, spontaneous, and pathologic. We present a case of a 40-year-old male with a history of bronchial asthma and a blunt chest trauma who presented complaining of sharp chest pain of acute onset that began after five consecutive days of vigorous coughing. Upon physical examination a well-demarcated deformity overlying the third intercostal space of the left upper anterior hemithorax was revealed. Thoracic CT scan showed that a portion of the anterior bronchopulmonary segment of the left upper lobe had herniated through a chest wall defect. The role of imaging, especially chest computed tomography with multiplanar image reconstructions and maximum (MIP) and minimum intensity projection (MinIP) reformats can clearly confirm the presence of the herniated lung, the hernial sac, the hernial orifice in the chest wall, and exclude possible complications such as lung tissue strangulation.

Keywords: Intercostal lung hernia; computed tomography; image reformats.

Figure 1

40 year old male with intercostal lung herniation. Scout view from chest CT. (A) Frontal view showed an area of increased radiolucency in the left upper lobe (white arrow). Lateral view (B) showing a well-circumscribed ovoid shape radiolucent lesion in the left hemithorax (black arrow). (C) and (D) show magnified views of frontal (A) and lateral view (B), respectively, confirming the presence of a radiolucent area in left upper lobe containing vascular markings.

Figure 2

40 year old male with intercostal lung herniation. Non-enhanced inspiratory chest computed tomography, mediastinal window, width/level of 350/30 HU, in coronal (A), sagittal (B) and axial plane (C) showing a region of air density in continuity with the left upper lobe protruding through a chest wall defect (black arrow). In the lung window, axial plane, width/level of 1500/−699 HU (D), the region proved to contain lung markings, belonging to the anterior bronchopulmonary segment of the left upper lobe (black arrow). The dimensions of the herniated lung parenchyma were calculated 5.45cm axially × 2cm antero-posteriorly × 4.7cm craniocaudally. (Protocol: GE LightSpeed VCT 64, 100 mAs; 120 kV, 1.3 mm slice thickness; 1.15 pitch)

Figure 3

40 year old male with intercostal lung herniation. Expiratory chest computed tomography, lung window (width/level of 1500/−599 HU) with Valsalva maneuver, in coronal (A), sagittal (B) and axial plane (C) where the herniated lung portion seems to protrude beyond the rib cage through a chest wall defect (black arrows). (Protocol: GE LightSpeed VCT 64, 100 mAs; 120 kV, 1.3 mm slice thickness; 20mm spacing)

Figure 4

40 year old male with intercostal lung herniation. Minimum intensity projection (MinIP, width/level of 668/−733 HU) in coronal plane (A) demonstrate no obvious signs of bronchial tree compression at the level of the lung herniation (black arrows). In maximum intensity projection (MIP, width/level of 1009/−488 HU) in sagittal plane (B) the herniated lung parenchyma shows no obvious signs of vessel compression or lung tissue strangulation (black arrows). (Protocol: GE LightSpeed VCT 64, 100 mAs; 120 kV, 1.3 mm slice thickness; 1.15 pitch)

Figure 5

40 year old male with intercostal lung herniation. Volume-rendered 3D reconstructions (VRT) in sagittal oblique plane presenting an overview of the intercostal lung hernia (A), protruding subcutaneously as a left upper chest wall well- circumscribed round area (black arrow), through a chest wall defect that corresponds to the hernial orifice (B) (black arrow), created by a costochondral junction fracture (white arrow) with subsequent intercostal muscle rupture (C).

Figure 6

40 year old male with intercostal lung herniation. Scout view from chest CT showing the herniated lung (white arrow) before (A) and (B) conventional postero-anterior chest radiography, 120kV, 500mA, after surgical repair of the chest wall defect (surgical clips, white arrows). Magnified views of the lung herniation before surgery where an area more radiolucent than normal lung parenchyma is depicted in the left upper lobe containing vascular markings (C) and after surgical repair (D) where left lung has normal and uniform radiolucency.