Basic information on congenital cystic lung diseases

2.  Congenital pulmonary airway malformation (CPAM) is a rare
condition characterized by immature, malformed lung tissue
with cystic appearance.
 CPAM is seen mainly in newborns and is rarely encountered
in older children and adults.
 Minimally symptomatic patients live up to adulthood and
experience frequent pneumonia, lung abscess formation and
life threatening haemoptysis.

3.  Ch'in and Tang in 1949 first described this developmental
anomaly as congenital cystic adenomatoid malformation
(CCAM).
 In 2002 Stocker renamed it as congenital pulmonary
airway malformation (CPAM) and classified in to 5 types.
 Exact etiology of CPAM is not known, it is to be
considered as hamartomatous malformation and abnormal
proliferation of the pulmonary tissue at different sites.

4.  Overall prevalence is 1 in 11000 to 1 in 35000 live
births.
 80% to 85% of cases are recognized in the first 2
years of life.
 Adult presentation is rare.
 Most CPAM in adults involve unilateral lobes of the
lung and may be complicated with pulmonary
bacterial infections and abscess.

5. Type Features
CPAM Type-0 Acinar dysplasia/agenesis is a rare malformation largely
incompatible with life
CPAM Type -1 It accounts for nearly 60-65% of cases. Lesion is predominantly
cystic type (measuring 3-10 cm in diameter) surrounded by smaller
cysts. It is operable and has a good prognosis.
CPAM Type II It accounts for 10%-15% of cases and mainly seen in first year of
life. Grossly lesion is composed of medium sized cysts measuring
0.5 to 2.0 cm in diameter. It has poor prognosis
CPAM Type III It is infrequent and accounts only about 5% of cases. It is small
cystic or solid type, exclusively seen in first few days to months of
life with characteristic male preponderance. It has high mortality
rate.
CPAM Type IV It accounts for 10%-15% of cases and presents as hamartomatous
malformation of the distal acinus. Lesion is grossly large, thin
walled cysts involving a single lobe.

6.  The symptoms and prognosis depend on the degree of
pulmonary involvement.
 The clinical presentation spectrum varies from
asymptomatic cases, recurrent pneumonia, or respiratory
insufficiency.
 In severe cases, patients develop respiratory failure even
in the neonatal period, but others have a benign clinical
course, with the manifestation of recurrent pneumonia

7. X-Ray shows a large cyst on the right side pushing the mediastinum to
left. CT thorax shows multiple cysts on the right side. Cysts are being
removed surgically.

8. X-Ray shows multiple cysts in the right upper zone (Red
arrows). HRCT shows a large cyst surrounded by multiple
small cysts (Black arrow).

9. X-Ray shows a thin walled cyst right lower zone (Black arrow). HRCT shows a large cyst
surrounded by multiple small cysts in the right lower lobe (Red arrow). Left lower lobe
shows resolving consolidation.

10. B
A
X-ray shows bilateral cystic lesions (yellow arrows). HRCT shows typical cysts
of CPAM on both lower lobes (Thick arrows).

11. X-ray shows cystic lesions right upper zone and left lower zone(red
arrows). HRCT shows typical cysts of CPAM on right upper lobe and left
lower lobe (Black arrows).

12.  Management of CPAM is surgical resection in early
life.
 Adult cases once diagnosed may be subjected to
surgery as chances of malignant transformation is
high.
 Bilateral lesion is a surgical concern due to risk of
life-threatening complications.
 Those who do not undergo surgery may be
conservatively managed with proper control of
infections, vaccination and pulmonary rehabilitation.

13.  Stocker type 1 and IV has good prognosis whereas
mortality is very high in Type II and III.
 Cysts are secondarily infected and leads on to lung
abscess.
 The association between CPAM and malignancy has
been well documented.