The glandular component in congenital cystic adenomatoid malformation of the lung

Association between Congenital Lung Malformations and Lung Tumors in Children and Adults: A Systematic Review

INTRODUCTION

The appropriate management of asymptomatic congenital pulmonary malformations (CPMs) remains controversial. Prophylactic surgery is recommended to avoid the risk for development of pulmonary infections and to prevent the highly debated development of malignancy. However, the true risk for development of malignancy remains unknown. A systematic review analyzed all cases in which lung tumors associated with CPMs in both the pediatric and adult populations were described.

METHODS

A comprehensive literature search was carried out; it included all the cases in which an association between CPMs and malignant pulmonary lesions was reported.

RESULTS

In all, 134 publications were eligible for inclusion. In 168 patients CPM was found associated with lung tumor. The diagnosis was made in 76 children at a mean age of 3.68 ± 3.4, whereas in the adult population (n = 92) it was made at a mean age of 44.62 ± 16.09. Cough was the most frequent presenting symptom both in children and in adults. Most of the patients underwent lobectomy. The tumor most often associated with CPM was pleuropulmonary bastoma in children (n = 31) and adenocarcinoma (n = 20) or bronchioloalveolar carcinoma (n = 20) in adults. The CPM most frequenty associated with tumors in children was congenital cystic adenomatoid malformation (n = 37), especially type 1 (n = 21), whereas in adults it was bronchogenic cyst (n = 25), followed by congenital cystic adenomatoid malformation (n = 21).

CONCLUSIONS

CPMs should be followed up and never underestimated because they may conceal a tumor. Apparently, there is no age limit for malignant progression of CPMs and no limit of the interval between first detection of the CPM and appearance of the associated tumor.

Pathology, toxicology, and latency of irritant gases known to cause bronchiolitis obliterans disease: Does diacetyl fit the pattern?

Bronchiolitis obliterans (BO) is a rare disease involving concentric bronchiolar fibrosis that develops rapidly following inhalation of certain irritant gases at sufficiently high acute doses. While there are many potential causes of bronchiolar lesions involved in a variety of chronic lung diseases, failure to clearly define the clinical features and pathological characteristics can lead to ambiguous diagnoses. Irritant gases known to cause BO follow a similar pathologic process and time course of disease onset in humans. Studies of inhaled irritant gases known to cause BO (e.g., chlorine, hydrochloric acid, ammonia, nitrogen oxides, sulfur oxides, sulfur or nitrogen mustards, and phosgene) indicate that the time course between causal chemical exposures and development of clinically significant BO disease is typically limited to a few months. The mechanism of toxic action exerted by these irritant gases generally involves widespread and severe injury of the epithelial lining of the bronchioles that leads to acute respiratory symptoms which can include lung edema within days. Repeated exposures to inhaled irritant gases at concentrations insufficient to cause marked respiratory distress or edema may lead to adaptive responses that can reduce or prevent severe bronchiolar fibrotic changes. Risk of BO from irritant gases is driven substantially by toxicokinetics affecting concentrations occurring at the bronchiolar epithelium. Highly soluble irritant gases that cause BO like ammonia generally follow a threshold-dependent cytotoxic mechanism of action that at sufficiently high doses results in severe inflammation of the upper respiratory tract and the bronchiolar epithelium concurrently. This is followed by acute respiratory distress, pulmonary edema, and post inflammatory concentric fibrosis that become clinically obvious within a few months. In contrast, irritant gases with lower solubility like phosgene also follow a threshold-dependent mechanism of cytotoxicity action but can exhibit more insidious and isolated bronchiolar tissue damage with a similar latency to fibrosis. To date, animal and human studies on the highly soluble gas, diacetyl, have not identified a coherent pattern of pathology and latency that would be expected based on studies of other known causes of bronchiolitis obliterans disease.

Congenital lung lesions

Confusion, controversy, and uncertainty are all terms applicable to the diagnosis and management of congenital lung lesions both prenatally and postnatally. This review examines the current status of fetal diagnosis and treatment of these lesions; reviews the various classifications, including congenital cystic adenomatoid malformation/congenital pulmonary airway malformation, sequestrations, variants and hybrid lesions; discusses the risk of malignant transformation or misdiagnosis with pleuropulmonary blastoma; presents the arguments in favor and against resection of asymptomatic lesions, the timing of such resection, and the long-term pulmonary function after resection; and reviews the experience with thoracoscopic resection of congenital lung lesions.

Squamous metaplasia in the cyst epithelium of type 1 congenital pulmonary airway malformation after thoracoamniotic shunt placement

Thoracoamniotic shunting is the treatment of choice for management of the fetus with type 1 congenital pulmonary airway malformation. Thoracoamniotic shunting has been performed to reduce life-threatening risks such as fetal hydrops. However, caution is needed because of possible complications. Here, we report that thoracoamniotic shunting can cause histologic changes in the cyst epithelia. In 5 of 8 patients treated prenatally with thoracoamniotic shunting, squamous metaplasia in the cyst epithelia was seen; whereas squamous metaplasia was not found in 6 patients who were not treated with this procedure. Our results reveal that long-term exposure to the intrauterine environment could possibly lead to the change in the nature of cyst epithelium and consequent squamous metaplasia.

MUC5AC, cytokeratin 20 and HER2 expression and K-RAS mutations within mucinogenic growth in congenital pulmonary airway malformations

AIMS

  To analyse the expression of several mucins (MUC1, MUC2, MUC3, MUC5AC and MUC6), epidermal growth factor receptor (EGFR), v-erb-b2 erythroblastic leukaemia viral oncogene homologue 2 (HER2), thyroid transcription factor-1 (TTF-1), caudal type homeobox 2 (CDX2) and cytokeratin 20 (CK20), and the presence of mutations of EGFR, KRAS and HER2 in congenital pulmonary airway malformations (CPAM).

METHODS AND RESULTS

  Forty-one cases of CPAM and six pulmonary sequestrations were included. TTF-1 expression was observed in all cases but was not seen in mucinogenic growths in CPAM. CDX2 expression was completely negative. MUC1 expression was noted in 12 (29%) CPAM and in 33% sequestrations. MUC5AC was noted in only five cases (26%) by immunohistochemistry and was found in the mucinogenic proliferations of type 1 CPAM. No immunolabelling was noted for the other mucins. EGFR was expressed variably in almost all cases, while HER2 and CK20 was seen exclusively in the mucinogenic proliferations. All mucinous growths were characterized by KRAS mutations. No EGFR and HER2 gene alterations were identified.

CONCLUSIONS

  KRAS mutations and MUC5AC, CK20 and HER2 expression was seen in all mucinogenic proliferations, supporting the neoplastic nature of these cytologically bland growths. These findings emphasize the importance of complete surgical resection of such lesions.

Cystic lung disease in infants and children

Cysts within the lung are one of the more common pulmonary pathological findings seen in an active pediatric surgical pathology service. Of both developmental and acquired origin, they may present as respiratory distress in infants or may be asymptomatic lesions incidentally discovered by images studies of the thoracic for "non-pulmonary" reasons. The most frequently seen developmental cysts of the lung are those of Congenital Pulmonary Airway Malformations, types 1, 2 & 4. Other congenital cystic lesions include bronchogenic cysts (usually in older patients) and some of the enteric duplication lesions that contain cysts. Acquired cystic lung lesions include acute and persistent pulmonary interstitial emphysema, postinfarction peripheral cysts, postinfectious pulmonary cysts, and the cystic form of pleuropulmonary blastoma.

Bronchioloalveolar carcinoma arising in a congenital pulmonary airway malformation in a child: case report with an update of this association

An 8-year-old girl was evaluated for a mass in the left pulmonary lobe. Her clinical history was remarkable for an intermittent dry cough since the age of 2, with recurrent episodes of purulent sputum and fever. She underwent left lower lobectomy, which was found to be a bronchioloalveolar carcinoma arising in a type 1 congenital pulmonary airway malformation at pathologic examination. No additional therapies were undertaken. Two years after resection, imaging studies showed 5 contralateral pulmonary nodules suggestive of disseminated disease with a poor outcome. A review of presentation, treatment, and outcome of this association was made.

Congenital cyst adenomatoid malformations: resect some and observe all?

With the advent of improved antenatal imaging over the past 10 years, the diagnosis, assessment and management of congenital cystic lung abnormalities have changed. These were once considered the exclusive domain of the surgeon, who had the authority to operate on all congenital cystic lung abnormalities regardless of size or clinical signs in order to avoid the risk of cancer and improve lung growth in even asymptomatic infants. Clinicians are reconsidering this approach in the light of an appreciation of the spontaneous improvement and possible resolution that occurs over months to years with many of these lesions. The risks of subsequent cancer are poorly understood and probably overstated, whereas the magnitude of compensatory lung growth is poorly defined in the majority of children with small unilateral congenital cystic abnormalities. The evolution of regional, national and ideally international databases will provide much-needed longitudinal data to better inform clinicians of the optimal way in which to manage these children.

Congenital cystic adenomatoid malformation associated with ipsilateral eventration of the diaphragm

A two-month-old girl was operated for a left-sided eventration of the diaphragm. At surgery, a mass representing an extralobar pulmonary sequestration (EPS) was found inferior to the left lobe of the lung and was excised. Histopathological examination of the resected specimen showed presence of a type II congenital cystic adenomatoid malformation (CCAM) within it. A review of the relevant literature is presented.

Imaging Evaluation of Congenital Lung Abnormalities in Infants and Children

Congenital lung abnormalities include a wide spectrum of conditions and are an important cause of morbidity and mortality in infants and children. This article discusses focal lung abnormalities and the dysmorphic lung. Pulmonary arteriovenous malformations have been included at the end of the article. Anomalies affecting the pulmonary parenchyma, its arterial supply, and venous drainage are thus discussed.

Asymptomatic congenital lung malformations

Congenital lung malformations are often discovered incidentally on routine prenatal sonography or postnatal imaging. Lesions such as congenital cystic adenomatoid malformations (CCAM), sequestrations, bronchogenic cysts and congenital lobar emphysema may be asymptomatic at birth or at the time of discovery later in life. Some authors advocate simple observation because of the lack of data on the incidence of long-term complications. However, there are very few described cases where CCAM and intralobar sequestration have remained asymptomatic throughout life; complications eventually develop in virtually all patients. The most common complication is pneumonia, which may respond poorly to medical treatment. Other complications include the development of malignancies (carcinomas and pleuropulmonary blastomas), pneumothorax and hemoptysis or hemothorax. Since lung resection will be required sooner or later for CCAM, intralobar sequestration and intrapulmonary bronchogenic cysts it is best not to wait for complications to occur. For patients diagnosed prenatally, we recommend surgery at 3 to 6 months of life at the latest, so that compensatory lung growth can occur. At this age the postoperative course is usually smooth and long-term follow-up has shown normal respiratory function. Mediastinal bronchogenic cysts also tend to become symptomatic and elective resection is recommended. On the other hand, asymptomatic congenital lobar emphysema may regress spontaneously and observation is warranted. The management of small noncommunicating extralobar sequestrations is more controversial; it is known that these lesions can remain asymptomatic throughout life but complications may develop and they are sometimes difficult to differentiate from neuroblastoma.

Sequestrations, congenital cystic adenomatoid malformations, and congenital lobar emphysema

The respiratory system begins to develop at 3 weeks gestation, and aberrations in developmental processes may give rise to a group of structural abnormalities collectively referred to as bronchopulmonary foregut malformations (BPFMs). These lesions or anomalies may subsequently present in the newborn period as pulmonary parenchymal abnormalities in association with significant respiratory compromise. This article briefly reviews fetal lung development and then proceeds to delineate the characteristics, presentation, and surgical treatment of 3 of the more common BPFMs, those being sequestrations, congenital cystic adenomatoid malformations, and infantile lobar emphysema. The various types of BPFMs may occur in conjunction with one another or in association with other congenital anomalies, and these lesions should be managed with a thoughtful and aggressive surgical approach.

The management of asymptomatic congenital lung malformations

Congenital Pulmonary Airway Malformation (CPAM) and lung sequestration are often discovered on routine prenatal sonography. While some lesions may be large and cause serious complications in the fetus or newborn, many will be asymptomatic at birth. Some authors advocate simple observation because of the lack of data on the incidence of long-term complications. However, there are very few described cases where CPAM and intralobar sequestration (ILS) have remained asymptomatic throughout life; complications eventually develop in virtually all patients. The most common complication is pneumonia, which may respond poorly to medical treatment. Other complications include the development of malignancies (carcinomas and pleuropulmonary blastomas), pneumothorax and hemoptysis or hemothorax. Since lung resection will be required sooner or later for CPAM and ILS, it is best not to wait for complications to occur. We recommend surgery at 3 to 6 months of life at the latest, to allow compensatory lung growth to occur. At this age the postoperative course is usually smooth and long-term follow- up has shown normal respiratory function. The management of small non- communicating extralobar sequestrations is more controversial; it is known that these can remain asymptomatic throughout life but complications may develop and they are sometimes difficult to differentiate from neuroblastoma.

Heterotopic pancreatic tissue presenting as a solid and cystic lung lesion: a very unusual bronchopulmonary foregut malformation

We describe the history and lung pathology of a premature female infant, who presented with respiratory distress immediately after birth. A thoracic computerized tomography scan showed abnormalities suggestive of congenital cystic adenomatoid malformation of the left lung. In addition, echocardiography revealed a tetralogy of Fallot. A left thoracotomy was performed and the lower lobe of the left lung was removed. Despite intensive supportive therapy, pulmonary hypoperfusion resulted in severe hypoxemia and death. Gross and microscopic analysis of the resected lobe revealed a partly cystic and solid lesion with multiple bronchus-derived cysts and an exuberant multifocal proliferation of glandular tissue, resembling bronchial glands, mixed with heterotopic cartilage surrounding ducts. Immunohistochemical analysis showed the presence of chromogranin A-reactive islet-like structures amidst exocrine tissue showing trypsin and chymotrypsin immunoreactivity, establishing the diagnosis of pulmonary pancreatic heterotopy. In the remaining pulmonary parenchyma, there were secondary changes consistent with partial obstruction and lymphangiectasis which was attributed to the presence of the cardiac malformation. To our knowledge, this is only the fourth reported case of heterotopic pancreatic tissue in the lung, and the first case where this bronchopulmonary foregut anomaly is not associated with a enteric duplication.

Malformação adenomatóide quística congénita do pulmão ou malformação congénita das vias aéreas pulmonares

The cystic adenomatoid malformation of the lung is an hamartomatous lesion, easily identifiable by its morphology through the application of Stocker's et al (1977) classification (type 1, 2 and 3) and also following the criteria of Yousem, to understand the five types dependent on the level of malformation in the airway and lung. The three morphological types described by Stocker were identified in 6 cases of the archive of the Department of Pathology of Coimbra's University Hospital, studied morphologically by the use of Movat's pentachromic stain and the application of the antibody anti-CK7 and anti-body anti-TTF1. In the three morphological types the elastic alveolar net is absent. The CK7 identifies the epithelial distribution and is useful to evaluate the extension of the inflammatory lesion. The antibody anti-TTF1, apparently absent in type 3 cases, is easily identified in type 1 and 2 cases and overexpressed in inflammatory areas. It seems that the absence of cells identified by the antibody anti-TTF1 prevents overdiagnosing of type 4 in Yousem's classification of congenital pulmonary airway malformation (CPAM).

The multiple facets of pulmonary sequestration

PURPOSE

The goal of this study was to identify the proportion of sequestrations that were atypical or associated with other entities, such as congenital cystic adenomatoid malformations, communicating bronchopulmonary foregut malformations, bronchogenic cyst, and scimitar syndrome.

METHODS

All charts of patients with pulmonary sequestration admitted at 2 children's hospitals from 1982 to July 1999 were reviewed retrospectively. The authors included all anomalies with a systemic arterial supply or without bronchial connection.

RESULTS

Only 22 of the 39 patients (56%) had a classic isolated extralobar or intralobar sequestration, whereas the others presented with a spectrum of anomalies. Of the 13 cases diagnosed prenatally, 85% were asymptomatic at birth. In contrast, 26 cases diagnosed postnatally were all symptomatic, with those patients less than 2 weeks old presenting with various degrees of respiratory distress, and those older than 2 weeks old presenting with respiratory infections. The correct diagnosis was made preoperatively in 59% of cases. Only 4 patients did not undergo resection of their lesion, of which, 1 underwent interventional radiology with embolization of the anomalous arterial supply. Follow-up issues of importance included pneumonia, asthma, gastroesophageal reflux, and pectus excavatum.

CONCLUSIONS

Sequestrations represent a spectrum of anomalies that overlap with other lung lesions. To facilitate management, they should be described according to their (1) connection to the tracheobronchial tree, (2) visceral pleura, (3) arterial supply, (4) venous drainage, (5) foregut communication, (6) histology, (7) mixed/multiple lesions, and (8) whether there are associated anomalies. Surgeons should be aware that approximately 50% of sequestrations could be atypical or associated with other anomalies. This should be kept in mind when weighing the benefits of resection versus conservative management of pulmonary sequestrations.