CASE ILLUSTRATIONMEDICINA 2018, Volume 49, Number 1: 53-58

P-ISSN.2540-8313, E-ISSN.2540-8321

53

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ABSTRACT

Congenital pulmonary airway malformation (CPAM) is one of four major congenital cystic lesion found inlungs. The incidence is relatively rare, characterized by dense multicystic areas of abnormal lung tissue. There are five types of CPAM described by Stocker classified according to the location of the development site of malformation. Type 4 is a rare type, thelesion contains large cysts, lined with flat alveolar cells, some of which contains surfactant. The case, a 2 monthold boy washospitalized

with chief complaint shortness of breath. Physical examination showedtachipnea and from the auscultation of the lung was hyper-resonance on the right side. Chest X-ray revealed suspected congenital emphysema on the right lung and multi slice CT scan revealed suspected CPAM type 1. Thoracotomy and bullectomy surgery was successfully performed and chest X-ray evaluation post-surgery showed no residual cystic lesion. Result from pathologic study showed it is CPAM type 4.

Keywords: congenital pulmonary airway malformation type 4, thoracotomy, bullectomy, childrenCite This Article: Lebao, A.A., Subanada,I.B., Suarta,I.K., Semadi, N. 2018. Congenital pulmonary airway malformation type 4 on a 2 month old boy. Medicina 49(1): 53-58. DOI:10.15562/medi.v49i1.265

ABSTRAK

Congenital pulmonary airway malformation (CPAM) merupakan salah satu dari empat lesi kistik utama di paru. Insiden kelainan ini relatif jarang, dengan karakteristik area multikistik padat pada jaringan paru-paru yang abnormal. Stocker membagi CPAM menjadi 5 tipe yang diklasifikasikan menurut lokasi malformasi. Tipe 4 merupakan tipe yang jarang, dimana lesi ini mengandung kista besar yang dikelilingi sel alveolar, dan kadang mengandung surfaktan. Kasus, laki-laki 2

bulan dengan sesak napas. Pada pemeriksaan fisis didapatkan takipneu dan pada auskultasi paru ditemukan hiper-resonansi pada sisi kanan. Hasil foto thoraks dengan kecurigaan emfisema kongenital dan CT scan thoraks dengan kecurigaan tipe 1 CPAM. Thoracotomy dan bullectomy berhasil dikerjakan dan pada evaluasi foto thoraks pasca-pembedahan tidak ditemukan adanya lesi residu. Hasil patologi anatomi menunjukkan suatu CPAM tipe 4.

Kata kunci: congenital pulmonary airway malformation tipe 4, thoracotomy, bullectomy, anakCite Pasal Ini: Lebao, A.A., Subanada, I.B., Suarta, I.K., Semadi, N. 2018. Congenital pulmonary airway malformation type 4 on a 2 month old boy. Medicina 49(1): 53-58. DOI:10.15562/medi.v49i1.265

Congenital pulmonary airway malformation type 4 on a 2 month old boy

Anastasia Asty Lebao,1* Ida Bagus Subanada,1 I Ketut Suarta,1 Nyoman Semadi2

INTRODUCTION

Congenital cystic lung disease in children is rare with various clinical presentations. Pulmonary sequestration, congenital pulmonary airway malformation (CPAM), congenital lobar emphy-sema, and bronchiogenic cysts are the four major congenital cystic lesion found in the lungs. The disease may result from compromised interaction between embryologic mesodermal and ectodermal lung components during intra uterindevelopment. Congenital cystic lung disease are reported to be CPAMabout 15-50% cases.1,2

Congenital pulmonary airway malforma-tion also known congenital cystic adenomatoid malformation (CCAM) is avery rare pulmonary disease in children, with a reported incidence between 1:25.000 and 1:35.000. Pathogenesis this

malformationremain unknown, however malfor-mation and abnormal proliferations of different sites of the airway are the basic for CPAM classifi-cation.2,3 The classification of CPAM using a system first described by Stocker in 2002 with five types, type 0-4.Type 4 CPAM accounts for 10-15% of CPAMs, type 4 cases were most likely considered within CPAM type 1 prior to 2002.4-6

Major clinical presentation is respiratory distress. Physical examination showed tachypnea, increased work of breathing, decreased breath sounds and hyper-resonance on the opposite of the lesions. A chest radiograph may identify a localised lesion. A thoracic CT scan is required to confirm the diagnosis.

Surgical resection is the gold standard of manage-ment for CPAM for both pathological diagnosis and

1Departments of Child Health and 2Cardiovascular and Thoracic Surgery,Udayana University Medical School, Sanglah Hospital, Denpasar, Bali

*Correspondence to: Anastasia Asty Lebao Departments of Child Health Udayana University Medical School, Sanglah Hospital, Denpasar, Bali anastasia@gmail.com

Diterima: 2018-01-01 Disetujui: 2018-01-25

Volume No.: 49

Issue: 1

First page No.: 53

P-ISSN.2540-8313

E-ISSN.2540-8321

Doi: http://dx.doi.org/10.15562/medicina.v49i1.265

Case Illustration

54 Medicina 2018; 49(1): 53-58 | doi: 10.15562/Medicina.v49i1.265

CASE ILLUSTRATION

treatment. Early pulmonary resection for asymp-tomatic CPAM is required and recommended to make a definite diagnosis and determine the prog-nosis. Malignancy and relapse are infrequent when radical surgery is not postponed.7

We report this case because CPAM is a very rare pulmonary disease in children. This is the first case of CPAM type 4 found in our hospital and the diagnose was finding coincidentally by X-ray performed.

CASE ILLUSTRATION

On April 22 2014, GAC, a 2 month old boy referred to Sanglah hospital with respiratory distress, suspected congenital emphysema. Parents complained of shortness of breath without bluish colour in mouth, tongue, and fingersince 3 days before admitted. Interruption of feeding was found in this patient.

He was born full-term, spontaneously, and was assisted by doctor. His birth weight was 3,200 grams and body length was 52 centimeters, no history of pulmonary congenital anomalies in his family, and he did not get any prior medications for specific diseases.

On physical examination, the patient showed shortness of breath, respiratory rate was 56 times per minute,heart rate was 136 beats per minute, peripheral oxygen saturation was 97% at room air, and axillary temperature was 36.8°C. His body weight was 5,2 kg and body length was 62 cm.

The head was normocephaly, sunken fontanel with head circumference was 40 cm. The hair was fine and black. The conjunctiva was not pale, no icterus on sclera, sunken eyes, and the pupil reflexes were normal. The ear, nose, and throat as well as neck

examination were normal. There was not any palpa-ble lymphnode. On chest examination we found no retraction in the chest wall, no precordial bulging, ictus cordis noticed on left mid-clavicle intercos-tals IV, and no murmur. No rales nor wheezing foundon chest auscultation, buthyper-resonance found on the right lung (Figure 1).

The initial complete blood count revealed WBC5.32K/µL (neutrophils15.6%, lymphocytes 74.8%, monocytes 4.7%, eosinophils 2.8% and basophils 0.2%), Hb 10.2 g/dl; MCV 78.8 fL, MCH 27.7g/dL, MCHC 35.1 g/dL, Hct 30.4% and platelets 341 K/µL. Blood gas analysis showed respiratoryaci-dosis and metabolic alkalosis. Coagulation factor and electrolytes were normal limit. Chest X-ray revealed suspected congenital emphysema on right lung with differential diagnose CPAM, hyper expanded right lung that pulled cardiac and thymus position to the left side, and right pleural effusion (Figure 2). Axial multi slice CT scan without contrastrevealed suspected CPAM type1 (Figure 3).

Thoracotomy and bullectomy procedure was successfully performed (Figure 4), and patient admitted to pediatric intensive care unit for 10 days,the first 5 days patient needs ventilator support, intravenous antibiotic, and analgetic (Figure 5). Chest X-ray evaluation post-surgery revealed suspected right suprahilarhematoma with differential diagnose of pneumonia, there was no cystic lesion (Figure 6). After clinical symptom of shortness of breath improved, the patient was transferred to ward.

One week after surgery, patients improved clinically, no shortness of breath,good nutrition intake,and no post-operative wound compli-cations. Pathologic result showed tissues with morphology form compatible with CPAM type 4. Routine complete blood examinationon May 7th, 2014, revealed WBC 7.81 K/µL (neutrophil 33.9 %, lymphocyte 52.9 %, monocyte 9.66 %, eosinophil 2.47 % and basophil1.06 %), Hb11.0 g/dL; MCV 84.2 fL, MCH 28.6g/dL, MCHC 34.0 g/dL, Hct 32.4 %, and platelet 185 K/µL. Blood gas anal-ysis and electrolyte were within normal limits. Blood culture analysis showed no microorganisms and procalciton in result was 0.07 ng/mL. Patient discharged on May 18th 2014and had no complaints after the surgery until now.

DISCUSSION

Congenital cystic adenomatoid malformation was first described by Ch’In and Tang in 1949,8 and now also known ascongenital pulmonary airway malformation due to the new classification system established by Stocker et al.3 Congenital pulmonary Figure 1 GACat 2 months of age at Sanglah Hospital

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CASE ILLUSTRATION

air malformation is characterized by dense multi-cystic areas of abnormal lung tissue. Histologically, the lesion of CPAM is characterized by solid adenomatous areas, which consist of closely packed tubular structures resembling terminal bronchioles without mature alveoli. These areas closely resem-ble normal foetal lung at 16 weeks of gestation. Postnatally the downstream alveoli can only be ventilated collaterally via the pores of Kohn.3

Congenital pulmonary air malformation is relatively rare, with a reported incidence between 1:25.000 and 1:35.000. Advanced in antenatal

ultrasonography (USG) will lead to higher inci-dence of CPAM, CPAM increasingly diagnosed. Congenital cystic lung disease are reported to be CPAM about 15-50% of cases. There is no differ-ence incidence between males and females.4,5

Majority cases (95%) of CPAM involve one lobe of lung, most often a lower lobe. There are five types of CPAM using a system described by Stocker,5 and was based on the hypothesis that each type corre-sponds to a perturbation along the airway from its proximal (bronchus) to distal segment (bronchio-alveolar sac). Types of CPAM are tracheobronchial (type 0), bronchial/bronchiolar (type 1), bronchio-lar (type 2), bronchiolar/alveolar (type 3), and distal acinar (type 4), classified according to the location of the development site of malformation.2,3,7 In our case, we found CPAM type 4.

Type 0 lesions are very rare, involves all lobes, patients will appear with still birth manifestation. Type 1is the commonest type of CPAM, often iden-tified antenatally, antenatal ultrasound examina-tion will reveal multiple large cysts (up to 10 cm) that may be asymptomatic. Type 1 lesion is usually unicystic or paucicystic and may contain fluid, they contain little or no adenomatous component. The cysts are greater than 2 cm in diameter and lined with pseudostratified columnar epithelium. Type 2 ismicrocystic, uncommon, and may be associated with other malformation. Type 2 lesion contain more uniform small cyst of less than 1 cm in diameter. Mucous cells and cartilage are seen in type 1, but not type 2. Type 3 is uncommon with solid lesion.2,6 Type 4 is also uncommon with lesion contain large cysts lineage with flat alveo-lar cells, some of which contain surfactant. They involve more peripheral lung. It can presents with tension pneumothorax.7 Type4CPAM was consid-ered within type 1, in older publications, as both typed are composed of large cysts (up to 10 cm in diameter).9 Large cysts are usually observed and pneumothorax can occur in type 1, which has a histological overlap with type 4 CPAM. It is not easy to differentiate between those two entities on histology alone.

Type 4 CPAM was described in 1990s and included in the CCAM to CPAM reclassification in 2002. Type 4 accounts for 10-15% of CPAMs, type 4 cases were most likely considered within CPAM type 1 prior to 2002.7,9 According to Stocker5, clin-ically and radiographically type 4 CPAM is not readily distinguished from other large-cysts lesion, type 1, however, tension pneumothorax may be a unique feature of type 4.7 In our case, there was no incidence of tension pneumothorax.

The pathogenesis of CPAM remain sun known, however malformations and abnormal

Figure 2 Chest X-ray showedsuspected congenital emphysema on therightlung with differential diagnose CPAM, hyperexpanded right lung that pulled cardiac and thymus position to the left side, and right pleural effusion

Figure 3 Axial multi slice CT scan without contrastshowed suspectedCPAM type1 at right lobe of the lung expanded to the heart and mediastinum to the left

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proliferations of different sites of the airway are the basic of CPAM classification. Various etiologies have been suggested to describe the pathogenesis of CPAM, among them overgrowth, hyperplasia, and hamartoma. However, all agreed that the defect occurred at the level of bronchiole. Stocker et al10 were first to attempt classification of CPAM types based on embryogenesis, or the developmental stage at which the insult may have occurred. The development of the vertebra lung, in fact, has been subdivided into five distinct periods based on the anatomical changes that occur in lung architecture: embryonic (3-7 weeks), pseudoglandular (7-17 weeks), canalicular (17-24 weeks), saccular (24-36

weeks), and alveolar (36 to maturity). Most CPAM develop during the pseudoglandular period when there is a rapid expansion of the conducting airways and peripheral lung tubules, which continue to branch and bud to form acinar tubules. Arrest in the phase of lung development involves the bron-chial type of epithelium causing CPAM pathology type 1-3 while a later arrest in weeks 22-36 in an alveolar acinar type CPAM pathology (type 4) of epithelium.6

Bronchography studies and serial microscopic examination showed that bronchial atresia is the primary defect leading to the development of CPAM. The morphology of the lesion, i.e. the type of malformation, is determined by the extent of dysplastic lung growth beyond theatretic segment.10

Modern pathological studies have suggested that CPAM may arise from failed interaction between mesenchyme and epithelium during development and a lack of maturation. Thus the discordance between vascularity and proliferation in CPAM may represent an arrest in vascular development and a loss of synchrony between stroma and epithe-lium.11 The imbalance between cell proliferation and programmed cell death or apoptosis has been demonstrated in CPAM. Investigation of other factors that down-regulate apoptosis or up-regulate proliferation in CPAM may further illuminate the pathogenesis of this entity.

For neonates, the size of the CPAM is typically correlated with the severity of clinical problem during pregnancy (hydrops, preeclampsia, poly-hydramnios) and diagnosed by antenatal ultra-sonography (USG). In our case, there were no abnormalities during pregnancy. Routine use of antenatal USG will lead to all cystic lung malfor-mations identified around 20 weeks gestation. The accuracy of antenatal diagnosis is a central issue in the care of the fetus with congenital cystic lung malformation. The advent of high-quality antenatal USG has dramatically changed the understanding of the evolution and involution of congenital cystic lung lesions such as CPAM. It is important that both the radiologist reporting the antenatal USG and the obstetrician caring the mother are fully informed about the outcome of congenital cystic lung lesions.12 In our case,the antenatal USG did not show the abnormality of the fetal lung.

The bigger the cystic lesion, the more severe the respiratory distress presented at birth. For infants and children, malformations communicate with the traheobronchial tree build valvular mechanism causing hyperinflation of the cystic zone during inspiration and less deflation during expiration. Enlarged cysts compressing the normal pulmonary

Figure 4 Operative view at thoracotomy showed cystic lesions with normal underlying lung (arrow)

Figure 5 Post-surgery in PICU ward

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structure lead to the respiratory symptoms. Granular tissue proliferation may cause mucin accumulation and recurrent infections.13-15

The majority of clinical presentations of CPAM in different ages have been reported as respiratory distress and failure in infants. Clinical presentation in later childhood was mainly with pulmonary infection, feeding difficulties, failure to thrive or, rarely, pneumothorax. Occasionally CPAM were detected coincidentally on a chest X-ray taken for other reasons.16 In our case,first clinical presenta-tion was respiratory distress.

Physical examination of the chest are tachypnea, increased work of breathing, decreased breath sounds and hyper-ressonance on the opposite of the lesions. A chest radiograph may identify a localised lesion. A thoracic CT scan is required to confirm the diagnosis. In our case,physical examination revealed tachypnea, decreased breath sounds and hyper-resonance of the right lung, a chest X-ray was shown a radioluscent lesion of the right lung, a CT scan shown suspected congenital pulmonary airway malformation type 1 at right lobe of the lung expand to the heart and mediasti-num to the left.

Air travel in children suffering from cystic lung lesions is controversial because of the risk of pneumothorax. Most clinicians caution against air travel in children with enlarging cystic lesions. All infants with antenatally diagnosed CPAM should be evaluated. Symptomatic children require surgi-cal resection.17 When CPAM is asymptomatic some clinicians prefer to observe rather than refer for surgery. However, when clinical presentation shows risks of pulmonary compression, infection, and the

low risk for malignancy, many clinicians prefer the operative approach.17,18 In our case, thoracoto-my-bulectomy surgery was performed.

A surgical complication rate of less than 10% was reported in one study on 47 infants, with only one lethal complication due to severe pulmonary hypertention post left side pneumonectomy.19 Lujan et  al16 reported a recurrent pneumonia and the misdiagnosis of spontaneous pneumothorax in children. Early surgical resection was performed without complication thereby preventing recurrent-pneumonia. To avoid the risks of repeate pulmo-nary infections and air tapping, radical surgery of the lesion once a diagnosis has been established was recommended.

The association between CPAM and malignancy has also been well documented. Malformation and proliferation cause harmatomas over the tracheo-bronchial tree. Type 1 CPAM involve malignant transformation of mucinous bronchilalevolar carci-noma.20 Type 4 CPAM requires examination of the entire lesion to exclude pleuropulmonaryblastoma by confirming whether or not sarcomatous differ-entiation is present in the solid parts.4 Even though malignant transformation is rare, the prognosis is very different from benign cystic lesion. Surgical resection is the gold standard of management for CPAM for both pathological diagnosis and treat-ment. However, emergency surgery incurs a higher rate of surgical complications due to prolonged chest tube drainage and wound infection. Early pulmo-nary resection during the asymptomatic period is recommended due to almost no reported cases of surgical mortality and satisfactory long-term outcomes.19 In our case,surgery was performed two weeks after the diagnosed established. There was no residual lesion and infection after surgery.

SUMMARY

Our case, GAC, a 2 month old boy referred to Sanglah hospital with respiratory distress, with suspect emphysema congenital. Patients were complained with shortness of breath without cyanotic since 3 days before admitted and also interruption of feed-ing due to shortness of breath. There was no history of pulmonary congenital anomalies in family.

The physical examination revealed shortness of breath without cyanotic, no rales norwheezing were heard on the auscultation, but hyper-ressonance found on the right side of lung. Laboratory exam-ination revealed normal routine blood analysis, blood gas analysis showed respiratoric acidosis and metabolic alkalosis. Chest X-ray revealed suspect congenital emphysema of the right lung with

Figure 6 Chest X ray evaluation post-surgery revealed suspected hemato-maon right suprahilar with differential diagnose of pneumonia, and there was no cystic lesion

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differential diagnose of CPAM. Multi slicedaxial CT scan without contrast shown suspect type 1CPAM .

Thoracotomy and bullectomy procedure was successfully performed. Chest X-ray evaluation post surgery revealed no residual cystic lesion.Pathologic study result showed tissues with morphology form compatible with CPAM type 4. Patient was discharged after 10 days post-surgery and had no complaints after the surgery until now.

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