Transcript Cystic Adenomatoid Malformation (CAM)

‫בס"ד‬
Congenital Cystic
Adenomatoid
Malformation (CCAM) of
the Lung

Dr Bental – NICU – Laniado Hospital

Congenital cystic adenomatoid malformation
(CCAM) of the lungs is a developmental
abnormality (hamartoma) arising at ~ the seventh
week of gestation from overgrowth of the terminal
respiratory bronchioles modified by
intercommunicating cysts (Stocker et al.
1977).Occurrence is sporadic unrelated to race,
maternal age, or familial genetic history.

In the fetus CCAM presents in association
with hydramnios, hydrops, prematurity, and
stillbirth.
Etiology/Pathophysiology

Congenital hamartomatous lesion of the
lung
Pathology

Cystic Adenomatoid Malformation
•Lower lobe of lung.
•Black arrow points to large cyst; yellow areas to smaller
cysts.
•White arrows highlight pleural surface.
•Portion of lung adjacent to pleura has normal apearance;
remainder shows enlarged spaces.
Pathology

There are 3 subtypes, all of which lack
normal bronchial communications:

Type I - multiple large air or fluid filled
cysts, usually greater than 2.0 cm in
diameter.
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AP and lateral chest radiographs show a well
defined cystic mass in the left lung. Type 1.

PA chest radiograph shows a cystic mass in the left
upper lobe
 Lung windows from an unenhanced CT scan of
the chest in the same patient better demonstrate
the cystic nature of the left lung mass.
 Type 1

Type II - variably sized less bulky lesion
with smaller cysts.
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Type III - bulky mass composed of
multiple tiny, microscopic cysts resembling
bronchi that involves the entire lobe.
Adenomatous hyperplasia with an increase
in terminal bronchiolar structures, as well as
a polypoid arrangement of mucosal
epithelium is seen.

Autopsy gross photograph showing the
abnormally enlarged left lung containing
multiple, small cysts.
Bilateral CCAM
Differential Diagnosis

Congenital lobar emphysema
 Bronchogenic cyst
 Bronchopulmonary sequestration
 Prior infection with pneumatocele formation
 Diaphragmatic hernia

Congenital Lobar Emphysema (CLE)
 Supine chest radiograph showing a large
cystic lucency in the left upper lobe.
ANTENATAL DIAGNOSIS

Type I CCAM appears as large cystic spaces
usually in the upper or middle lung .
 Type II appears as multiple small cysts < 1 cm on
a slightly echogenic background.
 Type III appears as an echogenic mass with no
cystic structure visible.

US of the fetus showing a large
mass in the thorax
ANTENATAL DIAGNOSIS

Polyhydramnios- Due to esophageal
compression (Donn et al., 1981), or
increased fetal lung fluid production by the
abnormal tissue (Krous et al., 1980)
 Fetal hydrops -From venocaval obstruction
and cardiac compression secondary to
mediastinal shift)
 Ascites

US showing integumentary edema
and ascites
FETAL THERAPY

Following a targeted ultrasound
amniocentesis and cardiac echo are
recommended to evaluate the fetus for
additional anomalies
 Prenatal MRI (?).
FETAL THERAPY

HYDROPIC FETUS
 In the hydropic fetus with an isolated
lesion prior to 32 weeks' thoracoamniotic
shunting is particularly useful
for alleviating mediastinal compression in
predominantly cystic CAM (Nicolaides K
and Azar GB, 1990, Thorpe-Beeston JG
1994) .
FETAL THERAPY

In cases not amenable to drainage (multiple small
cysts or Type III) referral for fetal lobectomy
should be considered .
 The hydropic fetus > 32 weeks' is better served by
ex utero lobectomy(Adzick NS, 1993).
 The major complications associated with surgical
interventions are premature labor and preterm
rupture of membranes
FETAL THERAPY

NONHYDROPIC FETUS
 The nonhydropic fetus with isolated CCAM
occupying < 50% of the thorax appear to do
reasonably well and may be followed with
serial exams (Dommergues M et al 1997).
Postnatal Clinical
Presentation

The most common presentation is acute
respiratory distress in the newborn in the
first few hours of life. Alternatively, it can
present at several months or several years of
age as recurrent pneumonias.
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Supine chest radiograph at one hour of life shows
a solid mass in the left hemithorax causing
mediastinal shift to the right, evidenced by the
position of the endotracheal tube.
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Supine chest radiograph at three hours of life in the same
patient shows a multiseptated cystic mass in the left
hemithorax causing mediastinal shift to the right.
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The chest-computerized tomograph demonstrates a right
lower lobe congenital cystic adenomatoid malformation
(CCAM) in a 6-week-old infant who presented with
tachypnea. The most striking feature is the solitary
enlarged cyst surrounded by a number of microcysts. This
lesion was resected without complication
POSTNATAL MANAGEMENT
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A significant number of CCAMs either
decrease in size or resolve in utero
spontaneously (Bromley B et al 1995 ) .
 However, Winters et al have demonstrated
persistent abnormalities after
birth in cases of "disappearing" fetal lung
masses.
POSTNATAL MANAGEMENT
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CT scan in the postnatal period is therefore
recommended as the findings are often subtle on
radiograph(Winters et al.,1997).
 Frequent infectious complications and malignant
change in CCAM argue for resection of these
tumors. (Granata et al ,1998, Kaslovsky RA et al
1997, d'Agostino S et al 1997, Ribet ME et al
1995)
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