Stocker classification | Alternate nomenclature | Genetic associations | Characteristics |
CPAM type 0 | Acinar dysplasia | TBX4-FGF10 pathway (germline) | - 1 to 3% of CPAM-type malformations
- Small cysts (<0.5 cm)
- Tracheal or bronchial origin
- Lethal at birth
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CPAM type 1 | | KRAS (somatic) | - 60 to 70% of CPAMs
- Single or multilocular thin-walled cysts (2 to 10 cm)
- Distal bronchi or proximal bronchiolar origin
- Course depends on cyst size
- Modest malignant potential; can be difficult to distinguish from type 4
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CPAM type 2 | Bronchial atresia-related cystic lung disease | | - 15 to 20% of CPAMs
- Small mixed solid-cystic lesions (0.5 to 2 cm)
- 80 to 90% have associated bronchial atresia
- May have associated extra and intralobar sequestration
- Often associated with other congenital anomalies*
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CPAM type 3 | | KRAS or BRAF (somatic) | - 5 to 10% of CPAMs
- Numerous small cysts (<0.5 cm); solid or mixed solid-cystic
- May involve an entire lobe or more
- Acinar origin
- Often severe respiratory distress at birth
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CPAM type 4 | PPB type 1 | DICER1 (germline) | - 5 to 10% of CPAM-type malformations
- Large thin-walled cysts (<7 cm), may be bilateral or multifocal, or single large air-filled cyst
- Radiographic appearance can be similar to CPAM type 1
- Strong malignant potential; considered a form of PPB
- Clues to the diagnosis:
- Often present with pneumothorax
- More likely if cysts are bilateral or multifocal
- May have a family history of DICER1 syndrome (PPB, ovarian or kidney tumors, or a variety of other malignancies)
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