Congenital Cystic Adenomatoid Malformation (CCAM)
Congential Pulmonary Airway Malformations (CPAM)
Congenital Pulmonary Airway Malformations [CPAM] (also called Congenital Cystic Adenomatoid Malformation[CCAM]) are developmental anomalies of the lower respiratory tract which occur in approximately 1 in 10,000 births. There are no known maternal factors such as age, race, or exposures. There are no known genetic predispositions or gender differences.
CPAMs result from an abnormality in the branching morphogenesis of the lung (the lung developed incorrectly). Different types are thought to originate at different stages and levels of development. The mechanism is unknown, but may be from imbalance during organogenesis (early organ formation). CPAM’s are hamartomatous (non-cancer) lesions comprised of cystic/adenomatous overgrowth of terminal bronchioles/airspaces. They normally connect to the tracheobronchial tree (airway) and pulmonary circulation (blood vessels). CPAMs can affect either side and any lobe, but rarely multiple lobes.
Types
Type 0: rarest, small lesions, mucus/cartilage present
Type 1: most common, lesions of distal bronchial, 2-10 cm lesions, mass effect
Type 2: small lesions, assoc. with congenital anomalies
Type 3: often very large, involves entire lobe
Type 4: rare, rarely contain cartilage
Presentation
Prenatal diagnosisis by ultrasound in almost all cases. Rarely, fetal hydrops (generalized swelling) in associated with CPAMs. Lesions regress in in size in about 59% cases and complete radiographic resolution may occur in a small number of cases. Of those children with with CPAMs, 50% with prenatal diagnosis are asymptomatic at birth
When diagnosed after birth, 2/3 present with respiratory symptoms, associated congenital anomalies, hydrops, or pulmonary hypoplasia (underdeveloped lungs). In childhood, thes are usually small lesions and patient may present with recurrent pneumonia, cough, dyspnea (difficulty breathing), or cyanosis (turning blue).
Diagnosis
Prenatal diangosis is by ultrasound; microcystic <5mm or macrocystic >5mm; fetal MRI can help to distinguish from CDH if diangosis is in question.
Postnatal diagnosis is usually by plain x-ray. Type 1 usually appears as single lesion, type 2 looks more bubbly, type 3 has more solid appearing lesion. All neonates with a prenatal diagnosis of CPAM should get a chest X-ray even if asymptomatic; One chest CT is often done prior to surgery to confirm the lesion is still present.
Treatment
Prenatal Treatment:
– A recent studies from Loh, et al from UCSF showed that fetuses with microcystic CCAM and hydrops fetalis benefit more from prenatal steroid treatment than from fetal surgery.[1]
– Fetal surgery is no longer recommended for CCAM, even with hydrops fetalis [1].
– Prenatal steroid treatment for microcystic CCAM and hydrops fetalis has shown benefit [1]
Postnatal and Symptomatic:
– Surgery is done urgently only in newborns in distress .
– Surgery is done electively in children with recurrent infection. Lobectomy is preferred, although some researchers suggest partial resections may be acceptable in some cases.
Postnatal and Asymptomatic:
– Surgery after the newborn period
– Excision of lesion prevents infection or malignancy
– Thoracoscopic (minimally invasive) resection may be available
CCAM and Malignancy
Pleuropulmonary blastoma (although rare) is difficult to distinguish from CCAM [1]
Bronchoalveolar carcinoma (BAC) and rhabdomyosarcoma (RMS) have been associated with CCAM’s
BAC-typically seen in adults, come from type 1 lesions
RMS-extremely rare in kids, unknown etiology
Outcome
Prognosis depends on type
Type 1: neonatal resection is curative, rest of lung undergoes compensatory growth
Type 2: outcome affected by severity of underlying congenital anomalies
Type 3: frequently have severe hypoplasia of the contralateral lung and often develop pulmonary hypertension
Controversies
Risk of Cancer: Oliveria et al from Canada retrospectively looked at the most common lung caner and compared it to CCAM. They were not able to distinguish the two reliably, even in retrospect. [2]
Timing of Surgery: early and late surgery in newborns have been proven safe. Our center recommend surgery at 6 to 12 months of age in infants without symptoms.
[1]. Loh K, Jelin E, Hirose S, Feldstein V, Goldstein R, Lee H. Microcystic congenital cystic adenomatoid malformation with hydrops fetalis: Steroids versus open fetal resection. Presented at 42nd APSA meeting in Palm Desert, CA on May 23, 2011
[2] Oliveira C, Himidan S, Pastor AC, Nasr A, Manson D, Taylor G, Yanchar NL, Brisseau G, Kim PC. Discriminating preoperative features of pleuropulmonary blastomas (PPB) from congenital cystic adenomatoid malformations (CCAM): a retrospective, age-matched study. Eur J Pediatr Surg. 2011 Jan;21(1):2-7. Epub 2010 Nov 22. PubMed PMID: 21104589.
[3] A, Himidan S, Pastor AC, Taylor G, Kim PC. Is congenital cystic adenomatoid malformation a premalignant lesion for pleuropulmonary blastoma? J Pediatr Surg. 2010 Jun;45(6):1086-9. PubMed PMID: 20620300.
[4] Laberge JM, Puligandla P, Flageole H. Asymptomatic congenital lung
malformations. Semin Pediatr Surg. 2005 Feb;14(1):16-33. Review. PubMed PMID:
15770585.
A Note on Prenatal Ultrasound Diagnosed Lung Abnormalities
Lung lesions are now commonly diagnosed on prenatal ultrasound. As prenatal ultrasound improved the diagnosis of lung lesions in the late 1990s, an effort was made to improve outcomes through fetal treatment centers. Only a few diseases (notably meningomyelocele and twin-twin transfusion) however, showed improved outcomes. Through a high quality trial, we now know that fetal intervention for lung lesions do not improve outcomes. Even for severe cases, such as those with ‘fetal hydrops,” results are better with maternal steroids than with fetal surgery. Our focus and efforts are directed toward minimally invasive newborn lung surgery in 2007.
In 2007, Dr. Kathy Graziano performed the first thoracoscopic formal lung lobectomy at Phoenix Children’s Hospital. While partial lung resections have been done for more than a decade, complete removal of the lobe (as required for some congenital lung lesions) had been considered too technically difficult. Newer devices to seal blood vessels allowed the new techniques to be developed. While these lesions do require much more skill than the open surgery, early adoption and over 5 years of experience has made this available for almost all prenatally diagnosed lung lesions such as CPAMs (Congenital pulmonary airway malformations) (also knows as CCAMs (Congenital cystic adenomatous malformations)), pulmonary sequestration (those with blood vessels coming from the aorta), as well as other miscellaneous lesions.
The surgeons at Pediatric Surgeons of Phoenix now prefer to remove these lesions thoracoscopically and any of our board certified surgeons are available to offer you and your baby the option of a minimally invasive removal.