• data collection
• epidemiology
• neonatology
• pathology

Alexander Pope’s line ‘A little learning is a dangerous thing’ (note: NOT knowledge) is probably one of the most misquoted in all literature, but certainly applies today to many rare diseases. An exemplar is congenital thoracic malformation (CTM, sometimes called congenital lung malformation, congenital pulmonary airway malformation, congenital cystic adenomatoid malformation and a host of other exotic names reflecting a lack of general consensus in management). We first learnt more than 30 years ago that large CTMs can be detected during the mid-pregnancy fetal anomalies scan. Without knowledge of the natural history of these lesions, there was an initial vogue for invasive fetal interventions until it became clear that the majority regressed to the extent that most babies were born well and required no immediate intervention.1 We also learnt that while most lesions remained asymptomatic for many years, serious complications may occur at any age in a small number. These fall into two categories: serious but treatable, such as infection, bleeding and pneumothorax; and the very rare but potentially lethal, namely malignant transformation and air embolism. The lack of knowledge of any biomarkers of adverse outcome, including imaging, has had the predictable result of different centres having different management strategies, variably operating on none, all or some. The field is an evidence-based desert in paediatrics and our relatively limited scientific insights into the biology of CTMs have made management harder, not easier. The recent welcome establishment of a neonatal registry (http://www.iclmr.org/) offers …