Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Congenital cystic adenomatoid malformation (CCAM), type I
- Radiologic Findings
- The chest PA shows ill-defined cystic mass with air-fluid level in left lower lobe. CT scan at the level of cardiac ventricle demonstrates multicystic mass in left lower lobe with consolidation.
- Brief Review
- CCAM occurs as adenomatous overgrowth of the terminal bronchioles, with subsequent suppression of alveolar growth. These lesions have intracystic communications and, unlike bronchogenic cysts, a connection to the tracheobronchial tree.
Stocker subclassified cystic adenomatoid malformations into three different types.
Type I malformation occurs as multiple large cysts (>2 cm in diameter), or as a single, large dominant cyst surrounded by numerous smaller cysts. Type I malformations are the most common form, accounting for up to 50% of cases.
Type II malformation makes up 42% of cases. These are described as multiple, evenly spaced cysts, mostly less than 2cm in diameter.
Type III malformation accounts for approximately 3% of the total. They are described as bulky microcystic lesions.
CCAM affects all lobes equally, and there is no right or left predominance.
Chest radiographic findings are variable and depend on the type of cyst present. Multiple air filled cysts are usually seen on the PA film. There is a depression of the ipsilateral diaphragm and a contralateral mediastinal shift. CCAM may change rapidly in size. Mucus retention or recurrent infection may lead to a granular or inhomogeneous appearance. The characteristic CT appearance consists of a localized complex cystic lesion and in the adult can be difficult to distinguish from sequestration.
Definitive treatment is removal of the affected lobe. Elective lobectomy is therefore the treatment of choice.
- References
- Keywords
- Lung, Congenital,