Congenital Cystic Adenomatoid Malformation

Question 1

What is CCAM?

Answer 1

Is a hamartomatous abnormality of the lung (abnormal tissue with an excess of one or more tissue components),
which results from adenomatoid proliferation of the terminal bronchioles resulting in the formation of cysts with a consequent reduction in alveolar growth.

Question 2

Classification of CCAM

Answer 2

Stocker classification
3 types , based on the cyst size

Adzick classification of CCAM into two types.

1. Microcystic CCAM − Cysts measuring < 5 mm in diameter
2. Macrocystic CCAM:
   − Cysts measuring > 5 mm in diameter

Question 3

Presentation

Answer 3

Respiratory distress

Recurrent chest infections due to bronchial compression, air trapping, and inability to clear secretions may be the presenting feature in those presenting later in life.

Cough, fever, and failure to thrive

Question 4

Respiratory distress in CCAM can be due to

Answer 4

Pulmonary hypoplasia 
− Mediastinal shift
 − Spontaneous pneumothorax 
− Air trapping within the cyst leading to compression of functional pulmonary tissue 
− Pleural effusion secondary to hydrops

Question 5

Differential diagnosis of CCAM

Answer 5

Congenital diaphragmatic hernia
Congenital pneumonia
Congenital lobar emphysema

Question 6

CCAM is differentiated from other congenital cystic disease of the lung by five characteristics:

Answer 6

Absence of bronchial cartilage (unless it is trapped within the lesion)

− Absence of bronchial tubular glands

− Presence of tall columnar mucinous epithelium

− Overproduction of terminal bronchiolar structures without alveolar differentiation, except in the subpleural areas

− Massive enlargement of the affected lobe that displaces other thoracic structures

Question 7

Diagnostics

Answer 7

Prenatal ultrasound- 
Prenatal MRI 
Chest X-ray 
CT scan 
Echocardiography to rule out other coexisting cardiac lesions

Question 8

Prenatal ultrasound in CCAM will reveal

Answer 8

Ultrasonography may also demonstrate evidence of hydrops, such as fetal ascites or pleural

effusions.

− Type I lesions appear as multiple large cystic areas in the lung.

− Type II lesions appear as multiple small cysts in the lung.

− Type III lesions and because of the extremely small size of the cysts they appear as a homogenous mass.

Question 9

Chest X-ray in CCAM will reveal

Answer 9

multiple cysts or a large cyst with or without adjacent smaller cysts or a mass containing air-filled cysts.

Other signs- mediastinal shift, pleural and pericardial effusions, and pneumothoraces.

Question 10

MRI will show ….. in CCAM

Answer 10

CCAM appear as intrapulmonary mass with increased signal intensity on T2-weighted images.

Question 11

Treatment of CCAM

Answer 11

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

Surgery intervention ( fetal surgery , postnatal surgery )

Prenatal-
A thoracoamniotic shunt is placed that continually drains fluid from the CCAM to the amniotic space.

Resection of the affected lobe (lobectomy

Postnatal- Resection of CCAM

Question 12

Complications associated with CCAM

Answer 12

Hemoptysis
Recurrent chest infection
Pneumothorax
Hemopneumothorax