Retrospective Evaluation of Children with Congenital Pulmonary Airway Malformation: A Single Center Experience of 20 Years

Pleuropulmonary blastoma type I might arise in congenital pulmonary airway malformation type 4 by acquiring a Dicer 1 mutation

Congenital pulmonary airway malformation (CPAM) occurs most commonly in infants. It is divided into 5 types. The most common types 1 and 2 are cystic, type 0 presents as bronchial buds without alveolar tissue, most likely corresponding to alveolar dysgenesis, while type 3 is composed of branching bronchioles and appears as a solid lesion. A defect in the epithelial-mesenchymal crosstalk might be the underlying mechanism for all. Type 4 is a peripheral cystic lesion with a thin cyst wall covered by pneumocytes. CPAM 4 has been mixed up with pleuropulmonary blastoma (PPB) type I and some authors question its existence. We investigated five cases of CPAM type 4 for the presence or absence of rhabdomyoblasts, and for markers associated with CPAM development. In addition, all cases were evaluated for mutations within the Dicer gene and for mutations of the RAS family of oncogenes. All five cases showed smooth muscle actin and desmin-positive cells; however, only one case showed a few cells positive for MyoD. The same case showed a mutation of Dicer 1. All cases were negative for mutations of the RAS family of genes. Fibroblast growth factor 10 was similarly expressed in all cases, and thus cannot be used to differentiate CPAM4 from PPB-I. Low expression of the proliferation marker Ki67 was seen in our CPAM 4 cases and the probable PPB-I case. YingYang-1 protein seems to play an active role in the development of PPB-I. CPAM 4 can be separated from PPB-I based on the presence of rhabdomyoblasts and mutations in Dicer 1 gene. These cells might not be numerous; therefore, all available tissue has to be evaluated. As CPAM 4 morphologically looks very similar to PPB-I, it might be speculated, that there exists a potential for progression from CPAM 4 to PPB-I, by acquiring somatic mutations in Dicer 1.

Outcomes in Children Undergoing Surgery for Congenital Pulmonary Airway Malformations in the First Year of Life

BACKGROUND

Treatment of congenital pulmonary airway malformations (CPAMs) is generally surgical resection; however, there is controversy regarding the optimal timing of surgical intervention, especially in asymptomatic patients.

STUDY DESIGN

Using the American College of Surgeons National Surgical Quality Improvement Program-Pediatric Participant Use Files from 2012 to 2015, children who underwent lung resection for CPAMs were identified. Outcomes in children who underwent lung resection during the neonatal period were compared with those who underwent resection beyond the neonatal period, but during the first year of life (non-neonates).

RESULTS

A total of 541 patients (20.7% neonates and 79.3% non-neonates) were identified. Neonates had higher rates of preoperative comorbidities and worse postoperative outcomes when compared with non-neonates (morbidity 19.6% vs 5.4%, p < 0.0001). On multivariable regression analysis, the presence of preoperative symptoms (defined as oxygen dependence or ventilatory support) was independently associated with increased morbidity (odds ratio 3.91 [range 1.6 to 9.57], p = 0.003). In a subgroup analysis of asymptomatic neonates compared with asymptomatic non-neonates, there was no difference in overall morbidity (7.4% vs 4.4%, p = 0.33).

CONCLUSIONS

These data suggest that lung resection for CPAMs in the neonatal period in asymptomatic children are not associated with increased 30-day morbidity. The presence of preoperative symptoms was independently associated with increased morbidity in a multivariable regression model. More data are needed to better understand the long-term outcomes and better define the optimal timing of surgery in this patient population.