Congenital Pulmonary Abnormalities IMAGING

Congenital cystic adenoid malformation IMAGING IS VERY ESSENTIAL

Bronchopulmonary foregut malformation:

  • Arise from a supernumerary lung bud that develops below the normal lung bud.
  • Location and communication with GIT depend on when in embryonic life the bud develops.
  • Most malformations present clinically when they become infected (communication with GIT).

Overview of Bronchopulmonary Malformations:

Malformation Location
Sequestration:

·        Intralobar

Sequestration

 

60% basilar, left

80% left or below diaphragm

Bronchogenic cyst Mediastinum, 85%; lung, 15%
CCAM All lobes
Congenital lobar emphysema LUL, 40%; RML, 35%; RUL, 20%

Pulmonary sequestration:

Clinical Findings:

  • Recurrent infection
  • Lung abscess
  • Bronchiectasis
  • Hemoptysis during childhood.

Pathology:

  • Non-functioning pulmonary tissue ànearly always posteromedial segments of lower lobes.
  • Systemic arterial supply à anomalous arteries from the aorta (less common branch of the celiac artery)
  • No connection to bronchial tree

Types of Pulmonary Sequestration:

                                                          

Feature Intralobar Sequestration Extralobar Sequestration
Age ·        Older children, adults ·        Neonates
Pleura ·        Inside lung (intralobar) ·        Outside lung àextralobar, own pleura)
Forms ·        Airless (consolidation) and air-containing, cystic type ·        Always airless (pleural envelope) unless à communication with GIT
Venous return: ·        Pulmonary vein ·        Systemic: IVC, azygos, portal
Arterial supply: ·        Thoracic aorta > abdominal aorta
Associations: ·        In 10% of patients:

o   Skeletal anomalies, 5%

o   Foregut anomalies, 5%

o   Diaphragmatic anomalies

o   Other rare associations

·        In 65% of patients:

o   Diaphragmatic defect, 20%

o   Pulmonary hypoplasia, 25%

o   Bronchogenic cysts

o   Cardiac anomalies

     

Radiographic Features:

  • Large (>5 cm) mass near diaphragm
  • Air-fluid levels if infected
  • Surrounding pulmonary consolidation
  • Sequestration may communicate with GIT.

Bronchogenic cyst:

  • It Results from the abnormal budding of the tracheobronchial tree. Cysts contain respiratory epithelium.

Location:

  • Mediastinum, 85% àposterior > middle > anterior mediastinum)
  • Lung, 15%

Radiographic Features:

o   Well-defined round mass in subcarinal / parahilar region

o   Pulmonary cysts commonly located in medial 1/3 of lung

o   Initially no communication with tracheobronchial tree

o   Cysts are thin walled.

o   Cysts can be fluid or air filled.

 

 

 

Congenital cystic adenoid malformation (CCAM):

  • CCAM refers to a proliferation of polypoid glandular lung tissue without normal alveolar differentiation.
  • Respiratory distress occurs during first days of life.

Treatment:

surgical resection (sarcomatous degeneration has been described).

Types:

Macrocystic:

(Stocker types 1 & 2)

o   single cyst or multiple cysts > 5 mm confined to one hemi-thorax.

o    Better prognosis.

o    Common.

Microcystic:

(Stocker type 3)

o   Homogeneous echogenic mass without discernible individual cysts.

o   Closely resembles pulmonary sequestration or intrathoracic bowel from a diaphragmatic hernia.

o   Less common.

Radiographic Features:

o   Multiple cystic pulmonary lesions of variable size

o   Air-fluid levels in cysts

o   Variable thickness of cyst wall

 

 

Congenital lobar emphysema:

  • Progressive overdistention of one or more pulmonary lobes but usually not the entire lung.
  • 10% of patients have congenital heart disease àpatent ductus arteriosus [PDA] & ventricular septal defect [VSD].

Causes:

  • Idiopathicà 50%
  • Obstruction of airway with valve mechanismà 50%:
  • Bronchial cartilage deficiency or immaturity
  • Mucus
  • Web, stenosis
  • Extrinsic compression

 

Radiographic Features:

o   Hyperlucent lobe (hallmark)

o   1.st few days of life à alveolar opacification because there is no clearance of lung fluid through bronchi

o   May be asymptomatic in neonate but becomes symptomatic later in life

o   Use CT to àdifferentiate from bronchial obstruction

o   Distribution

§  LUL, 40%

§  RML, 35%

§  RUL, 20%

§  2 lobes affected, 5%

 

Pulmonary hypoplasia:

Types of Pulmonary Underdevelopment:

  • Agenesis: Complete absence of one or both lungs (airways, alveoli, & vessels).
  • Aplasia: Absence of lung except for a rudimentary bronchus that ends in a blind pouch.
  • Hypoplasia: decrease in number and size of airways and alveoli; hypoplastic PA.
  • Scimitar Syndrome (Hypogenetic Lung Syndrome, Pulmonary Venolobar Syndrome)

– A special form of a hypoplastic lung.

– The hypoplastic lung is àperfused from the aorta & drained by the IVC or portal vein.

– The anomalous vein has a resemblance to a Turkish scimitar (sword).

– Associations include:

   1) Accessory diaphragm, diaphragmatic hernia

   2) Bony abnormalitiesà hemivertebrae, rib notching, rib hypoplasia

   3) CHD: atrial septal defect (ASD), VSD, PDA, tetralogy of Fallot

 

 

  • Radiographic Features:
o   Small lung àmost commonly the right lung.

o   Retrosternal soft tissue density à hypoplastic collapsed lung.

o   Anomalous vein resembles a scimitar

o   Systemic arterial supply from aorta

o   Dextroposition of the heart àshift because of hypoplastic lung)

 

Congenital diaphragmatic hernia (CDH):

Incidence:

  • 1 in 2000 to 3000 births.
  • The mortality rate of isolated hernias is 60% (with postnatal surgery) and higher when other abnormalities are present.
  • Respiratory distress occurs in the neonatal period.
  • Associated abnormalities include:

Pulmonary hypoplasia (common)

CNS abnormalities:

Neural tube defects : spina bifida, encephalocele Anencephaly

Types:

Bochdalek’s hernias: Ø 90% of CDH à posterior:

o   75% are on the left, 25% on right

o   Right-sided hernias are more difficult to detect because of similar echogenicity of liver & lung.

o   Contents of hernia:

ü Stomach, 60%.

ü Colon, 55%.

ü Small intestine, 90%.

ü Spleen, 45%.

ü Liver, 50%.

ü Pancreas, 25%.

ü Kidney, 20%.

o   Malrotation of herniated bowel is very common.

Morgagni hernias: Ø 10% of CDH à anterior:

o   Most occur on right (heart prevents development on the left).

o   Most common hernia contents: omentum, colon

o   Accompanying anomalies common

Eventration: o   Due to relative absence of muscle in dome of diaphragm

o   Associated with:

ü Trisomies 13, 18, congenital CMV, rubella arthrogryposis multiplex, pulmonary hypoplasia

  • Radiographic Features:
o   Hemi-diaphragm not visualized

o   Multi-cystic mass in chest

o   Mass effect

 

Kartagener syndrome (immotile cilia syndrome):

  • Due to the deficiency of the dynein arms of cilia causing immotility of respiratory, auditory, & sperm cilia.

Radiographic Features:

o   Complete thoracic & abdominal situs inversus

o   Bronchiectasis

o   Sinus hypoplasia & mucosal thickening

YOU CAN SEE REAL CASE IMAGES AT THIS LINK:

https://radiopaedia.org/articles/congenital-pulmonary-airway-malformation

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