Congenital pulmonary airway malformation

Opposing roles for TGFβ- and BMP-signaling during nascent alveolar differentiation in the developing human lung

Alveolar type 2 (AT2) cells function as stem cells in the adult lung and aid in repair after injury. The current study aimed to understand the signaling events that control differentiation of this therapeutically relevant cell type during human development. Using lung explant and organoid models, we identified opposing effects of TGFβ- and BMP-signaling, where inhibition of TGFβ- and activation of BMP-signaling in the context of high WNT- and FGF-signaling efficiently differentiated early lung progenitors into AT2-like cells in vitro. AT2-like cells differentiated in this manner exhibit surfactant processing and secretion capabilities, and long-term commitment to a mature AT2 phenotype when expanded in media optimized for primary AT2 culture. Comparing AT2-like cells differentiated with TGFβ-inhibition and BMP-activation to alternative differentiation approaches revealed improved specificity to the AT2 lineage and reduced off-target cell types. These findings reveal opposing roles for TGFβ- and BMP-signaling in AT2 differentiation and provide a new strategy to generate a therapeutically relevant cell type in vitro.

Congenital pulmonary airway malformation in a 5 month old boy, complicated by pneumonia

Congenital cystic lesions of the lung are rare. The most common congenital anomaly among them, involving the lower respiratory tract, is congenital cystic adenomatoid malformation (CCAM), currently referred to as congenital pulmonary airway malformation (CPAM). They may be incidentally detected on prenatal or postnatal imaging. They usually present within two years of life, rarely in adults. CPAMs may be asymptomatic at birth. Some may opt for observation alone due to lack of evidence on the incidence of long-term complications. However, rarely has a CPAM remained asymptomatic throughout life and complications eventually develop. Pneumonia is most common, which is not amenable to medical treatment alone. CPAMs are notorious for their known malignant potential and they may also lead to pneumothorax, hemoptysis and hemothorax. Computed Tomography Thorax is the investigation of choice. Surgical resection is known to be safe and is the mainstay of treatment. For patients who are diagnosed prenatally, surgery is recommended at 3 to 6 months, so that compensatory lung growth can occur. A five-month old boy from Bhutan, with cough, intermittent fever, respiratory distress and a history of recurrent lower respiratory tract infections, was diagnosed with CPAM, complicated by pneumonia and underwent surgery at our centre, following optimal medical management viz. antibiotics and supplemental oxygen. The post-operative course was relatively uneventful and he was discharged from hospital in 7 days.

Opposing roles for TGFβ- and BMP-signaling during nascent alveolar differentiation in the developing human lung

Alveolar type 2 (AT2) cells function as stem cells in the adult lung and aid in repair after injury. The current study aimed to understand the signaling events that control differentiation of this therapeutically relevant cell type during human development. Using lung explant and organoid models, we identified opposing effects of TGFβ- and BMP-signaling, where inhibition of TGFβ- and activation of BMP-signaling in the context of high WNT- and FGF-signaling efficiently differentiated early lung progenitors into AT2-like cells in vitro . AT2-like cells differentiated in this manner exhibit surfactant processing and secretion capabilities, and long-term commitment to a mature AT2 phenotype when expanded in media optimized for primary AT2 culture. Comparing AT2-like cells differentiated with TGFβ-inhibition and BMP-activation to alternative differentiation approaches revealed improved specificity to the AT2 lineage and reduced off-target cell types. These findings reveal opposing roles for TGFβ- and BMP-signaling in AT2 differentiation and provide a new strategy to generate a therapeutically relevant cell type in vitro .

Congenital Pulmonary Airway Malformation - A Histomorphological Spectrum of 15 Cases: A 5-Year Study from a Tertiary Care Center

Objective:

Congenital pulmonary airway malformation (CPAM) is a rare developmental lung disease. The aim of this study is to analyze the histomorphological spectrum of CPAM in a series of 15 cases.

Materials and Methods:

A retrospective descriptive study of 15 cases of CPAM was carried out from 2013 to 2018 in our hospital, and cases were classified based on the Stocker's classification.

Results:

The age ranged from 4 days to 9 years (66.6% were infants). The left lung was most commonly involved (66.6%). The most common lobe was the left upper lobe (60%), followed by right lower lobe (20%). Grossly, cysts measured 0.2–5 cm, filled with mainly serous fluid with few having hemorrhagic and brownish mucoid secretions. On microscopy, single to multiple noncommunicating cysts of size 0.2–5 cm were seen, lined by ciliated columnar epithelium (60%), pseudostratified ciliated columnar epithelium (26.7%), mucin-secreting columnar epithelium (6.7%), and flattened epithelium (6.7%). Few cases showed smooth muscle (20%) and cartilage (13.3%) in the cyst wall. Chronic inflammation (73.3%) with dense histiocytic infiltrate (13.3%) was also seen. Emphysematous changes were also observed (13.3%). Cytomegalovirus inclusions (6.7%), zygomycete fungus (6.7%), and red hepatization (6.7%) were observed. The most common type was type II (60%), followed by type I (33.3%) and type IV (6.7%).

Conclusion:

Type II was the most common variant in this study. A careful observation should be done to look for fungal hyphae or viral inclusions.

Pediatric Congenital Lung Malformations: Imaging Guidelines and Recommendations

Congenital lung malformations are a spectrum of developmental anomalies comprised of malformations of the lung parenchyma, airways, and vasculature. Imaging assessment plays a pivotal role in the initial diagnosis, management, and follow-up evaluation of congenital lung malformations in the pediatric population. However, there is currently a lack of practical imaging guidelines and recommendations for the diagnostic imaging assessment of congenital lung malformations in infants and children. This article reviews the current evidence regarding the imaging evaluation of congenital lung malformations and provides up-to-date imaging recommendations for pediatric congenital lung malformations.

Unusual Congenital Lesion Masquerading as a Lung Mass in an Adult

Congenital pulmonary airway malformation (CPAM) is a broad spectrum of congenital cystic lung lesions caused by the arrested bronchoalveolar development. Approximately, 80% of CPAMs are diagnosed prenatally or during the neonatal period when patients present with respiratory failure and cyanosis. CPAM is often associated with other organ anomalies and aplasia, and they have poor prognoses. Many CPAMs are detected in infants and school-age children, and infections like pneumonia trigger these diagnoses. It rarely manifests in adults. These often get missed because of the superadded diseases, and hence, it is essential to have a correct approach to their diagnosis to avoid misdiagnosis.

Developmental Pathways Underlying Lung Development and Congenital Lung Disorders

Lung organogenesis is a highly coordinated process governed by a network of conserved signaling pathways that ultimately control patterning, growth, and differentiation. This rigorously regulated developmental process culminates with the formation of a fully functional organ. Conversely, failure to correctly regulate this intricate series of events results in severe abnormalities that may compromise postnatal survival or affect/disrupt lung function through early life and adulthood. Conditions like congenital pulmonary airway malformation, bronchopulmonary sequestration, bronchogenic cysts, and congenital diaphragmatic hernia display unique forms of lung abnormalities. The etiology of these disorders is not yet completely understood; however, specific developmental pathways have already been reported as deregulated. In this sense, this review focuses on the molecular mechanisms that contribute to normal/abnormal lung growth and development and their impact on postnatal survival.