Figure 1
Chest X-ray PA
PA chest radiograph showing large cyst in the right upper lobe, with downward displacement of the minor fissure and compression of the right middle lobe.
Progressive emphysematous lung changes in a 15 month-old boy: an acquired or congenital anomaly ?
SectionPaediatric radiology
Case TypeClinical Cases
AuthorsVliegen AS, Breysem L, De Boeck C
Connected authors
15 months, male
Clinical History
A 15-month-old boy presented with fever (38.9°) and tachypnoea. Physical examination showed a small boy: height: 69,5 cm (P25), weight 8,9 kg (P25-P50). He had eczematous skin lesions on his cheeks and legs. Breath sounds on lung auscultation were normal. There where no known respiratory problems in his clinical history.
Imaging Findings
A chest X-ray revealed a cystic lesion in the right upper lobe, seen as a hyperlucent region devoid of bronchovascular markings, associated with secondary compression of normal lung parenchyma in the right middle lobe and medial aspect of the right upper lobe. The left lung was normally aerated.
A further chest radiograph performed one week later, showed the cyst to have increased in volume.
A chest CT exam was subsequently performed, which showed a septated, thin-walled, cystic lesion in the right upper lobe. No bronchovascular bundles were identified within the lesion. There was compression of the remaining parenchyma of the right upper lobe, and the adjacent right middle lobe.
The left lung was seen to be normally aerated, and no associated cardiac or mediastinal abnormalities were present.
A further chest radiograph performed one week later, showed the cyst to have increased in volume.
A chest CT exam was subsequently performed, which showed a septated, thin-walled, cystic lesion in the right upper lobe. No bronchovascular bundles were identified within the lesion. There was compression of the remaining parenchyma of the right upper lobe, and the adjacent right middle lobe.
The left lung was seen to be normally aerated, and no associated cardiac or mediastinal abnormalities were present.
Discussion
The differential diagnosis of a hyperlucent expansile thoracic lesion in a child of this age would include: congenital lobar overinflation, congenital pulmonary airway malformation, and a (post)infectious pneumotocele.
Because of his age, infantile lobar overinflation or CLO (previously known as congenital lobar emphysema or CLE) can be excluded, as this condition more often presents in infants prior to the age of 6 months with inceasing respiratory distress, and is not associated with cyst formation at imaging.
Congenital pulmonary airway malformation or CPAM (previously known as congenital cystic adenomatoid malformation or CCAM) is an uncommon congenital hamartomatous lesion of the lung with overgrowth of bronchioles and nearly total suppression of alveolar development. the cysts communicate with the tracheo-bronchial tree and with one another, and gradually fill with air after birth. Typically a whole or part of a lobe are involved; multiple lobe involvement has been reported. There is a male predominance.
The vast majority of patients present in the direct neonatal period or following a diagnosis made by antenatal ultrasound. Late presentation in older children and adults occasionally occurs. Infants with CPAM may have symptoms of respiratory distress, vomiting, failure to thrive or recurrent pneumonias.
The original Stocker classification recognised three distinct sub-types, based upon the size of the cysts:
Type I is the most common type, with cysts of 2-10cm seen. A single dominant cyst may be present and progressive expansion of the lesion may occur.
Type II shows heterogeneous areas of uniform small cysts (<2cm diameter), sometimes fluid-filled.
Type III appears as a parenchymal consolidation or a mass on chest X-ray or computed tomography. This type is rarely recognised post-natally.
Stocker's classification was recently extended to include types 0 and 4, based upon the presumed site of maldevelopment of the airway (moving from the central airway to the peripheries).
(Post)infectious pneumotoceles should also be included in the differential diagnosis, although we didn't expect this because there where no respiratory problems in his medical history and pneumatoceles are most often acquired as a sequel to acute pneumonia, especially after a Staphylococcal aureus pneumonia. They are generally observed soon after the development of pneumonia but may be seen on the initial chest radiograph. They can enlarge slowly and are predominately localised in the periphery of the upper lobes. Initially, when they develop, they may have thick walls. Later they develop thin, smooth walls.
As this lesion increased in volume and the child's respiratory problems worsened, the boy was operated upon and the cystic lesion in the right upper lobe was removed.
The cystic resection specimen was examined by the pathologists, who confirmed the diagnosis of a pneumatocele. Although there was no (known) pneumonia in his history, we concluded that this pneumatocele was a post-infectious finding.
Because of his age, infantile lobar overinflation or CLO (previously known as congenital lobar emphysema or CLE) can be excluded, as this condition more often presents in infants prior to the age of 6 months with inceasing respiratory distress, and is not associated with cyst formation at imaging.
Congenital pulmonary airway malformation or CPAM (previously known as congenital cystic adenomatoid malformation or CCAM) is an uncommon congenital hamartomatous lesion of the lung with overgrowth of bronchioles and nearly total suppression of alveolar development. the cysts communicate with the tracheo-bronchial tree and with one another, and gradually fill with air after birth. Typically a whole or part of a lobe are involved; multiple lobe involvement has been reported. There is a male predominance.
The vast majority of patients present in the direct neonatal period or following a diagnosis made by antenatal ultrasound. Late presentation in older children and adults occasionally occurs. Infants with CPAM may have symptoms of respiratory distress, vomiting, failure to thrive or recurrent pneumonias.
The original Stocker classification recognised three distinct sub-types, based upon the size of the cysts:
Type I is the most common type, with cysts of 2-10cm seen. A single dominant cyst may be present and progressive expansion of the lesion may occur.
Type II shows heterogeneous areas of uniform small cysts (<2cm diameter), sometimes fluid-filled.
Type III appears as a parenchymal consolidation or a mass on chest X-ray or computed tomography. This type is rarely recognised post-natally.
Stocker's classification was recently extended to include types 0 and 4, based upon the presumed site of maldevelopment of the airway (moving from the central airway to the peripheries).
(Post)infectious pneumotoceles should also be included in the differential diagnosis, although we didn't expect this because there where no respiratory problems in his medical history and pneumatoceles are most often acquired as a sequel to acute pneumonia, especially after a Staphylococcal aureus pneumonia. They are generally observed soon after the development of pneumonia but may be seen on the initial chest radiograph. They can enlarge slowly and are predominately localised in the periphery of the upper lobes. Initially, when they develop, they may have thick walls. Later they develop thin, smooth walls.
As this lesion increased in volume and the child's respiratory problems worsened, the boy was operated upon and the cystic lesion in the right upper lobe was removed.
The cystic resection specimen was examined by the pathologists, who confirmed the diagnosis of a pneumatocele. Although there was no (known) pneumonia in his history, we concluded that this pneumatocele was a post-infectious finding.
Differential Diagnosis List
Post-infectious pneumatocele
Final Diagnosis
Post-infectious pneumatocele
References
[1] Berrocal T, Madrid C, Novo S, Gutierrez J, Arjonilla J, Gomez-Leon N (2004) Congenital Anomalies of the Tracheobronchial Tree, Lung, and Mediastinum: Embryology, Radiology, and Pathology. Radiographics 24:e17 (PMID: 14610245)
[2] Melissa L, Stocker JT (1991) Congenital cystic adenomatoid malformation. Radiographics
[3] Kubiman JE, Reyes BL, Hruban RH, Askin FB, Zerhouni EA (1993) Abnormal air-filled spaces in the lung. Radiographics 13:47-75 (PMID: 8426936)
[4] Godwin JD, Webb WR, Savoca CJ, Gamsu G, Goodman PC (1980) Multiple thin-walled cystic lesions of the lung. AJR 135:593-604 (PMID: 6773384)
[5] Quigley MJ, Fraser RS (1988) Pulmonary Pneumatocele: Pathology and Pathogenesis. AJR 150:1275-7 (PMID: 3259364)
Case information
| URL: | https://www.eurorad.org/case/8102 |
| DOI: | 10.1594/EURORAD/CASE.8102 |
| ISSN: | 1563-4086 |
Figure 2
Lateral chest X-ray
Lateral chest radiograph confirms the cystic lesion to lie in the upper lobe.
Figure 3
Chest X-ray PA
Frontal chest X-ray performed one week later; the cyst has increased in size and is now clearly seen to be septated. There is partial right middle lobe atelectasis.
Figure 4
Coronal chest computed tomography
Coronal MPR image from CT study; this confirms the right upper lobe multiloculated cyst, and right middle lobe compression/partial collapse.
Figure 5
Resection specimen of the cyst
Normal small alveoles on the left side of the image and a piece of the large pneumatocele on the right side. The pneumatocele is lined by a layer of hyperplastic mesothelium cells.
Chest X-ray PA
PA chest radiograph showing large cyst in the right upper lobe, with downward displacement of the minor fissure and compression of the right middle lobe.
Lateral chest X-ray
Lateral chest radiograph confirms the cystic lesion to lie in the upper lobe.
Chest X-ray PA
Frontal chest X-ray performed one week later; the cyst has increased in size and is now clearly seen to be septated. There is partial right middle lobe atelectasis.
Coronal chest computed tomography
Coronal MPR image from CT study; this confirms the right upper lobe multiloculated cyst, and right middle lobe compression/partial collapse.
Resection specimen of the cyst
Normal small alveoles on the left side of the image and a piece of the large pneumatocele on the right side. The pneumatocele is lined by a layer of hyperplastic mesothelium cells.