Pediatric pulmonology 2021 year in review: Rare and diffuse lung disease.

The field of rare and diffuse pediatric lung disease is experiencing rapid progress as diagnostic and therapeutic options continue to expand. In this annual review, we discuss manuscripts published in Pediatric Pulmonology in 2021 in (1) children's interstitial and diffuse lung disease, (2) congenital airway and lung malformations, and (3) noncystic fibrosis bronchiectasis including primary ciliary dyskinesia. These include case reports, descriptive cohorts, trials of therapies, animal model studies, and review articles. The results are put into the context of other literature in the field. Each furthers the field in important ways, while also highlighting the continued need for further studies.