congenital cystic adenomatoid malformation

1. Cysts of lungs
Dr Hammad ur Rehman
PGR, PSW, SHL

2. A 28-year-old female is 27 weeks pregnant
whose prenatal ultrasound reveals a 3.5 cm
cystic echogenic mass in the left lower lobe.
What is D/D of echogenic lesion in fetal
thorax?
What USG findings are associated with poor
outcomes?
How will you manage the fetus?

3. D/D of echogenic lesion in fetal thorax
•CCAM
•Broncho pulmonary Sequestration
•Congenital lobar emphysema
•Congenital diaphragmatic hernia

6. 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

7. • CCAM represents approximately 25 % of all congenital
lung malformations.
• CCAM generally communicates with the bronchial
tree.
• Its has blood supply from the pulmonary circulation
(in contrast to pulmonary sequestration, which derives
its blood supply from the aorta)

8. • Lower lobe is most commonly involved.
• Equal left and right sided incidence.
• No gender predominance.
• Associated anomalies are very rare.

11. Type I Type II Type III
Multiple large cysts (> 2 cm in
diameter).
multiple small cysts, usually
<1 cm in diameter.
entirely adenomatoid, foam-
like mass with multiple small
(< 0.5 cm) cysts.
Variable sized cysts Uniform cysts Appear solid
Ciliated pseudostratified
epithelium
ciliated cuboidal or columnar
epithelium
Low Cuboidal epithelium
Excellent prognosis Associated with other
congenital anomalies that
may affect prognosis, Renal
Agenesis

12. Additional Types
Type 0 Type 4
Acinar dysplasia or agenesis
Incompatible with life
Large peripheral cyst of the distal
acinus
lined with alveolar type cells
Associated with malignancy

16. Types

17. Prenatal classification of CCAM based on USG
Macrocystic Microcystic
Single or multiple cysts >/=
5mm diameter
<5 mm diameter cysts
Usually not associated with
hydrops
Usually associated with fetal
hydrops
Favorable prognosis Poor prognosis

18. •Microscopically, the lesions are not true cysts, but
communicate with the surrounding lung
parenchyma.
•Type II and III lesions can occasionally coexist with
extralobar sequestration.(Hybrid)
•Associated with Polyhydramnios.
•CCAM may also occur in association with a
polyalveolar lobe.

19. Pathophysiology
•The pathophysiologic effects of CCAM may be
divided into prenatal and postnatal.
•Large lesions may be associated with the
development of hydrops fetalis.
•Compromised pulmonary growth.

20. •The usual postnatal presentation of CCAM is a
respiratory distress in the newborn period.
•This may be due to:
Pulmonary hypoplasia
Mediastinal shift
Spontaneous pneumothorax
Air trapping within the cyst leading to compression
Pleural effusion secondary to hydrops

21. • CCAM may also remain undiagnosed until it is discovered as
an incidental finding later in life.
• Recurrent chest infections.
• Hemoptysis, Cough, fever, and failure to thrive
• A risk of malignant transformation in later years is also
noted.
• Prenatal regression and complete resolution of CCAM have
also been described.

22. CCAM is distinguished from other lesions and
normal lung by
1. Polypoid projections of the mucosa.
2. An increase in smooth muscle and elastic tissue
within cyst walls.
3. An absence of cartilage.
4. The presence of mucus-secreting cells.
5. The absence of inflammation.

23. Investigations
Prenatal Post Natal
Antenatal USG CXR
MRI Post natal USG
CT Scan/MRI

24. Imaging – Prenatal USG
• Earliest diagnosis made at 16 weeks.
• The diagnosis is usually made in the 2nd trimester.
• USG:
Identifies the location of the lung abnormality by its
appearance
Evaluate the blood supply & venous drainage by doppler
Determine changes in position of other lung lobes, med &
cardiac structures.

25. • 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.

26. • Ultrasonography may also demonstrate evidence of
hydrops, such as fetal ascites or pleural effusions.
• Prenatal ultrasonography is accurate in diagnosing
CCAM.
• Prenatally diagnosed lesions may be asymptomatic at
birth (71 %), and they may have normal radiographic
findings (57 %).

27. Prognosis
• If no hydrops by 26 weeks Good Prognosis.
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

28. • The following features are suggestive of poorer
prognosis in unilateral lesions:-
Mediastinal shift
Fetal hydrops
Polyhydramnios
Associated anomalies
CVR > 1.6

29. • CCAM volume- The CCAM volume is estimated using the
formula
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.

30. • CCAM with a CVR > 1.6 are at high risk for the
development of hydrops and fetal demise (up to 80%).
• Such malformations should be followed with twice-
weekly Ultrasound scans so that fetal surgery can be
undertaken at the earliest signs of hydrops.

31. • If the CVR is < 1.6 - favorable prognosis. The risk of
developing hydrops is < 2 %. The only exceptions are
malformations with a “dominant cyst.”
• These lesions can enlarge acutely, do not follow a
predictable pattern of growth and hence must be
followed closely.
Dominant cysts are those that comprise greater than one-third of the entire volume of the CCAM.

32. Fate
• The natural history of CCAM is near exponential
growth, from 20 weeks gestation until the plateau is
reached which is around 28 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.
• May enlarge in 10% of the cases.

33. A 28-year-old female is 27 weeks pregnant with a
fetus whose prenatal ultrasound reveals a 3.5 cm
cystic mass in the left lower lobe. There is no
mediastinal shift and no hydrops. The next step in
management should be:
• Counselling for termination of pregnancy
• Intrauterine drainage of the mass
• Observation with serial ultrasounds
• Placement of thoracoamniotic shunt
• In utero excision of the mass.

34. Antenatal management

36. • In the presence of large unilocular cysts and hydrops,
consideration can be given to drainage of the cysts by
thoraco-amniotic shunting.
• Microcystic CCAM with CVR > 1.6 and/or hydrops = maternal
IV betamethasone.
• Laser ablation and injection of sclerosing agents have also
been described in the treatment of microcystic CCAM.

37. • In patients with large, solid CCAM with associated
hydrops, open fetal surgery is indicated.

38. 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

39. •Even asymptomatic masses are removed d/t
Risk of secondary infection
Hemorrhage
Carcinoma
Prevents development of normal lung

40. Post natal (neonatal) imaging-CXR
• Type I lesions -Chest radiographs typically show a
unilateral, airfilled, multicystic lesion in the thorax.
• Demonstrate an air-filled cystic radiographic
appearance.
• Mediastinal shift and mass effect on the ipsilateral
hemidiaphragm.

43. • 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.

44. Post natal USG

45. CT Scan
• The typical appearance is a multilocular cystic lesion
with thin walls surrounded by normal lung
parenchyma.
• Multiple large cystic lesions (> 2 cm in diameter) are
seen alone or with other abnormalities.
• Cyst with Air Fluid level
• CCAM may completely resolve but persistent
abnormalities are well demonstrated on CT
examination.

49. Magnetic resonance imaging
• MRI permits increased definition and accurately
diagnoses CCAM.
• MRI may be useful particularly in distinguishing CCAM
from congenital diaphragmatic hernia.

50. Other imaging studies:
• Renal and cerebral ultrasonography to exclude
coexisting renal and CNS anomalies.
• Echocardiography to rule out any coexisting cardiac
lesions.
• Echocardiography may provide evidence of persistent
pulmonary hypertension.

51. Post natal management
• Patients with CCAM complicated by pneumonia should be
treated with antibiotics and supportive care, ranging from
oxygen supplementation to mechanical ventilation.
• 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.

52. • 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%.