Information sources
The systematic literature search was performed in the PubMed, Embase, Scopus and Cochrane library, which was conducted by two investigators independently by using medical subject headings and search terms: ‘Cystic Adenomatoid Malformation of Lung, Congenital’, ‘Asymptomatic Diseases’ and ‘Surgical Procedures, Operative’. A combination of MeSH words and Entry terms was used in our search. Other potential studies were identified through manual searching of the eligible studies. Two researchers independently reviewed the publications and studies and selected the articles identified with specific inclusion criteria presented. Disagreement was resolved by consensus involving a third reviewer. To improve the transparency, accuracy and completeness, this meta-analysis is written and conducted in accordance with the guidelines from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) guidelines for conducting and reporting systematic reviews.