This document discusses Congenital Cystic Adenomatoid Malformation (CCAM), a rare pulmonary developmental abnormality. It describes the characteristics and types of CCAM including pathogenesis, imaging findings, prognosis, management, and differentiation from other conditions. Key points: 1) CCAM is comprised of pulmonary tissue with abnormal bronchial proliferation forming cysts. It occurs in 1 in 25,000 live births and is usually limited to one lobe. 2) Prenatal ultrasound can detect cystic or solid masses. Larger lesions with hydrops carry a poorer prognosis. Fetal interventions like shunting may be considered. 3) Surgical resection is often needed after birth for large or symptomatic

1. D R . S N E H A S . V O L V O I K A R
M O D E R A T O R S : D R . R A G H U R A M P .
D R . J A I P A L B . R .
CONGENITAL CYSTIC
ADENOMATOID
MALFORMATION

2. Congenital pulmonary airway
malformation (CPAM) spectrum
CCAM (Congenital
cystic adenomatoid
malformation)
BPS
(Bronchopulmonary
sequestration)
CLE (Congenital
lobar emphysema)

3. What is CCAM?
 Rare pulmonary developmental hamartmatous
abnormality
 Comprised of pulmonary tissue with abnormal bronchial
proliferation
 The fundamental pathologic feature of the lesion is
adenomatoid proliferation of bronchioles that form cysts
at the expense of normal alveoli

4.  25% of all congenital lung masses
 1 in 25000 live births
 >95% are limited to 1 lobe or segment
 2-3% are B/L

5. Pathogenesis
Pulmonary insult during development of
bronchial tree
Failure of bronchial maturation & lack of
normal alveoli
Absence of bronchial cartilage & tubular
glands
Overpdn of terminal bronchiolar structures
without alveolar differentiation

6. Characteristics
 Has a normal communication with the T-B tree
 Normal vascular supply & venous drainage to
pulmonary circulation UNLESS asso with
sequestration (type II & III)
 Lined by respiratory epithelium

7. Types
Type I Type II Type III
Features 2-10 cms cyst < 2 cms cysts <0.5 cm cysts
Variable sized
cysts
Uniform cysts Appear solid
ciliated
pseudostratified
epithelium
ciliated cuboidal
or columnar
epithelium
shows
adenomatoid
elements
consistent with
distal airway

8. Stage of
development
Gestatio
nal age
Description Typ
e
Embryonic 26days- 6
weeks
‘Lung bud’ derived from primitive foregut
and branches dichotomously to form the
early tracheobronchial tree
Pseudoglandul
ar
6- 16
weeks
Airways develop to the level of terminal
bronchioles but end blindly within primitive
stroma
III
Canalicular 16-28
weeks
Multiple alveolar ducts arise from
respiratory bronchioles and are lined by
Type II pneumocytes
II
Saccular 28-34
weeks
Increase in number of terminal sacs,
thinning of interstitium, proliferation of
capillary bed
I
Alveolar 34-36
weeks
Mature alveoli are composed exclusively of
alveolar lining cells, basement membrane,
cap endothelium

9. Additional types
Type 0 Type IV
Acinar dysplasia or agenesis Large peripheral cyst of the
distal acinus lined predom with
alveolar type cells
Associated with malignancy,
specifically pleuropulmonary
blastoma.

10. CCAM
CPAM
Because only 3 out of 5
are cystic
AND
Only 1 is adenomatoid

11. Prenatal classification of CCAM based on USG
Macrocystic Microcystic
Single or multiple cysts >/=
5mm diameter
<5 mm diameter cysts
Seen on USG as cysts, difficult to
identify normal lung on same
side
Appear as a solid
hyperechogenic mass bec of
numerous acoustic interfaces
Favourable prognosis Poorer prognosis

12. Pre natal Post natal
 Antenatal USG
 MRI
 CXR
 CT scan (once air
filled)
 Post natal USG
Imaging of CCAM

13. Imaging – Prenatal USG
 Earliest diagnosis made at 16 weeks. The diagnosis is
usually made in the 2nd trimester, but sometimes in the
3rd trimester when referred for investigation of
polyhydramnios.
 USG:
 identifies the location of the lung abnormality by its
appearance
 evaluate the blood supply & venous drainage by doppler
 determine changes in posn of other lung lobes, med &
cardiac structures

14.  Solid, echogenic lung mass
OR
 Mixed solid cystic mass
OR
 Sometimes, only a single large cyst
 Color doppler- vascular flow to the lesion from a
branch of the pulmonary artery.

15. To predict outcome
 CCAM volume- The CCAM volume is estimated using the
formula for a prolate ellipse
CCAM= (Length x Height x Width x 0.52 )
 A CVR is obtained by dividing the CCAM volume (cc) by
the head circumference (cm) to correct for differences in
the fetal gestational age.

16.  If the CVR is < 1.6 - favorable prognosis. The risk of developing
hydrops is less than two percent in these cases. The only exceptions
are malformations with a “dominant cyst.”
 Dominant cysts are those that comprise greater than one-third of
the entire volume of the CCAM.
 These lesions can enlarge acutely, do not follow a predictable
pattern of growth and hence must be followed closely.
 Those congenital cystic adenomatoid malformation with a CVR >
1.6 are at high risk for the development of hydrops and fetal demise
( up to 80 percent of cases).
 Such malformations should be followed with twice-weekly
ultrasound scans so that fetal surgery can be undertaken at the
earliest signs of hydrops.

17.  All congenital cystic adenomatoid malformation
should be followed once in 2 weeks for measurement
of CAM volume and CVR until the growth of CCAM
reaches a plateau.
 Weekly follow up if hydrops

18. Longitudinal section of thorax showing a
large cystic lesion
Cross-section view.The large cystic
lesion is seen in the right hemithorax.
The heart is compressed and deviated
to the left (arrow). Skin oedema and
polyhydramnios

19. Type 2 congenital cystic adenomatoid malformation (CCAM). A,
Sagittal image of a fetus at 24 weeks with Type 2 CCAM located in the
posterior chest (arrows). B, Transverse image with measurements
showing the inferior extent of the lesion. The mass is multicystic and
located inferior and posterior to the heart. Arrowhead indicates the
stomach.

20. Transverse image of a fetus at
20 weeks with Type 3 congenital cystic
adenomatoid malformation demonstrating
its position posterior and to the left of the
heart. The heart is displaced to the right.

21. Associated findings/ Complications
 Mediastinal shift
 Polyhydramnios
 Hydrops
Determine
prognosis &
Mx

22. Complications
If large CCAM
Cardiac compression
Altered hemodynamics &
increased CVP
Hydrops- mortality- 100% if
untreated

23. Associated anomalies
 Usually isolated and rarely associated with chromosomal
defects.
 Associated anomalies include
 Renal
 Cardiac (truncus arteriosus & TOF)
 CNS & spinal defects
 Abdominal wall defects.
 Type II CCAM is more commonly associated with other
anomalies.
 Elevated alpha-feto protein has been reported with type III
CCAM.

24. MRI
 Type I & II- very high SI on T2
- equal to amniotic fluid
- higher than surrounding normal lung
 Type III- moderately high SI
- homogenous
- as they regress- SI drops
- asso with pleural effusion

25. Coronal T2-weighted MR image shows a well-
circumscribed area of T2 hyperintensity (arrow) in the left
upper lobe.
Oblique coronal T2-weighted MR image shows a well-
circumscribed area of low T2 signal, in a fetus with a
typical, resolving CCAM.

26. Prognosis
 If no hydrops by 26 weeks  Good. Therefore, surveillance done every
2 weeks during the 2nd trimester
 Unilateral type I CCAM (macrocystic lesion) in the absence of hydrops
and polyhydramnios - Good prognosis
 The following features are suggestive of poorer prognosis in unilateral
lesions:-
 large size cysts
 mediastinal shift
 fetal hydrops
 polyhydramnios
 associated anomalies

27.  Bilateral CCAM is lethal
 Type 0 CCAM is considered lethal.
 Resection of Type 1 CCAM is considered to be curative and outcomes are
excellent.
 Outcomes for Type 2 CCAM depend largely on the presence of associated
anomalies.
 The risk of pulmonary hypoplasia is highest with Type 3 CCAM, given its
tendency for growth and mass effect & earlier development of hydrops and
polyhydramnios. Pulmonary hypoplasia cannot, at this time, be predicted
antenatally.

28. Fate
 The natural history of CCAM is near exponential
growth, from 20 weeks gestation until the plateau is
reached which is around 26 weeks
 CCAMs tend to regress during 3rd trimester (30-
40%). As they regress, they become isoechoic to lung,
eventually becomes inapparent in later gestation
 In half of the cases there is no change in the size of
the lesion, while it may enlarge in 10% of the cases.

29. Antenatal management

30. Fetal interventions
 In the presence of large unilocular cysts and hydrops, consideration can be
given to drainage of the cysts by thoraco-amniotic shunting.
 Multicystic or predominantly solid CCAM are not suitable for catheter
decompression and require resection. Laser ablation and injection of
sclerosing agents have also been described in the treatment of
microcystic CCAM, in which cysts are too small for decompression.
 Fetal thoracocentesis alone is ineffective because of the rapid
reaccumulation of cyst fluid.
 The relief of associated polyhydramnios by serial amniocentesis has also
shown to be of value
 In patients with large, solid CCAM with associated hydrops, open fetal
surgery is indicated.

31. Post natal manifestations
 40% with prenatal diagnosis are symptomatic at birth-
acute progressive respiratory distress occurring shortly
after birth with cyanosis, grunting, retractions, and
tachypnea.
 Require intervention or respiratory support (ECMO)
with NICU admission
 Even asymptomatic masses are removed d/t
1. Risk of secondary infection
2. Hemorrhage
3. Carcinoma
4. Prevents development of normal lung

32.  Patients may present in early infancy with symptoms of
respiratory distress, vomiting, failure to thrive, and
recurrent pneumonia.
 Patients may also present in childhood and adulthood
with recurrent infection localized in the involved lobe

33. Post natal (neonatal) imaging-CXR
 Type I lesions -Chest radiographs typically show a unilateral,
airfilled, multicystic lesion in the thorax.
 Homogeneous fluid-opacity pulmonary mass may present and
evolve to demonstrate an air-filled cystic radiographic
appearance.
 The lesions may be very large and may occupy the entire
hemithorax, producing mediastinal shift and mass effect on the
ipsilateral hemidiaphragm.
 The abnormally expanded lung may be herniated across the
midline.
 The uninvolved ipsilateral and contralateral portions of the lung
may be atelectatic or hypoplastic due to compression.

34.  Type II lesions may appear as heterogeneous areas of
uniform small cysts
 Type III lesions are usually large and homogeneous,
having the appearance of parenchymal consolidation
or a mass rather than that of a cystic lesion

35. Initial anteroposterior radiograph of
the chest in a patient with congenital
cystic adenomatoid malformation on
the first day of life, with dense lungs
and a suggestion that the right lung is
slightly more voluminous than the left
lung.
On the second day of life (same patient as in
previous image), an anteroposterior
radiograph shows physiologic fluid
resorbed from an area of congenital cystic
adenomatoid malformation and replaced
with an air-containing cystic area occupying
the right upper lung.

36. Type I lesion in an asymptomatic male
newborn. (a) Frontal chest radiograph obtained for
evaluation of right-sided cardiac sounds shows multipIe
air-filled cysts occupying the left hemithorax. The
cyst walls are thin. There is marked mass effect on the
mediastinum, with displacement to the right. (b) Axial
computed tomographic (CT) image of the thorax
shows multiple thin-walled, air-filled cysts of variable
sizes in the left lung. The lesion produces mass effect
on the mediastinum

37. CT Scan
 Areas of small cysts (< 2 cm in diameter) or multiple large
cysts appearing with other abnormalities (a larger cystic
area, consolidation, or low attenuation) are the most
frequent findings.
 Low-attenuation areas are clusters of microcysts.
 Air-fluid levels can be seen in some cysts. These lesions
may be predominantly type I, type II, or a combination of
both.

38. Computed tomography scan
of the neonate, performed
on day of life 1. There is a 0.9x 0.9 cm
mass with several cysts within the medial
segment of the right lower lobe. No
systemic vessels can be seen supplying
the mass. Findings are consistent with a
Type 2 congenital cystic adenomatoid
malformation.

39. CT scan of the chest demonstrating a multiseptated
cystic lesion in the right upper lobe consistent with
localized congenital cystic adenomatoid
malformation.

40. Chest radiographs obtained on day 2 and 3
of life show an expanding, air-filled cystic
lesion (white and yellow arrows) in the
right lower lobe. The newborn also had
hyaline membrane disease.
A CT scan of the same child shows a cystic
lesion in the right lower lobe with
septations (green arrow) and an air-fluid
level (blue arrow).

41. Post natal USG
 The complex internal appearance of multiple fluid-
filled areas with internal septations or solid elements
representing the cyst walls can be demonstrated
 Echogenic, solid-appearing thoracic masses may be
seen in patients with type III lesions.

42. Post natal management
 In the case of respiratory compromise, resection is indicated and is
curative with minimally invasive surgery
 Elective surgery within few months after birth
 Early resection may allow for compensatory lung development in
the remaining tissue
 Surgical management of CCAM involves lobectomy- suggested for
CCAM because of risks of incomplete resection, which occurs in 15%
 In symptomatic neonates the survival following postnatal
thoracotomy and lobectomy is about 90%.

43. D/D of echogenic lesion in fetal thorax
Abnormality Location Distinguishing feature
CCAM U/L (2-3%- B/L) Cystic & solid
Sequestration U/L (left LL-mc) Systemic blood supply
Congenital lobar
emphysema
U/L (UL- most often) Similar to microcystic
CCAM; enlarged
echogenic lung
with mediastinal shift,
prog lung expansion,
absence of internal linear
opacities
Congenital diaphragmatic
hernia
U/L (left side more
common)
Peristalsis of bowel in
chest, stomach above
diaphragm, absence of
part of the diaphragm

45. Computed tomography scan of a neonate . There is a solid soft
tissue density within the left lower lobe measuring approximately
3 cm 3 2 cm. A small vessel arising from the descending aorta is
seen supplying this solid mass (arrows); findings are consistent
with sequestration. The baby underwent resection of the mass at
3 months of age.

46. D/D- Cystic lesion in fetal thorax
Abnormality B/L v/s U/L Distinguishing
features
CCAM U/L (2-3% - B/L) Associated with echogenic
lung mass, typically
multiple cysts
CDH Typically U/L Peristalsis of bowel in
chest, stomach above
diaphragm(abs st bubble)
Cystic Teratoma Mass does not obey lobar
boundaries; may have
calcifications.

47. Abnormality Distinguishing feature
Neurenteric cyst Adjacent to spine
Bronchogenic cyst Typically single cyst,
direct connection with
upper airway
Esophageal duplication Adjacent to esophagus
Lymphangioma Crosses anatomic
boundaries