Asymptomatic pulmonary nodules in the paediatric population – a literature review

Pulmonary nodules are mostly solitary focal opacities typically round or oval in shape, with a diameter of less than 3 cm. They are surrounded by aerated lung parenchyma or located subpleurally, and are not associated with abnormalities, such as lymphadenopathy or atelectasis. Pulmonary nodules are found in up to one-third of computed tomography scans taken in adults, whereas they are significantly less common in children. In adult patients, incidentally detected pulmonary nodules are more frequently associated with neoplastic processes, while they are primarily related to congenital disorders or inflammatory conditions in paediatric populations. The identification of single or multiple pulmonary nodules should always prompt an attempt to determine the likely aetiology. The so-called idiopathic nodules, for which no definitive cause can be established, are a particular subgroup. Although the majority of these lesions are benign in children, some may represent an early stage of malignancy. Due to the lack of standardised management guidelines for the paediatric population, clinical decisions regarding follow-up and further diagnostic workup are often challenging. This literature review outlines the potential causes of incidentally detected paediatric pulmonary nodules, from malignant tumours to other diseases that can present in this form, and discusses methods for assessing the malignant risk of pulmonary nodules in paediatric patients. Finally, a management strategy is proposed for asymptomatic pulmonary nodules detected on imaging, computed tomography in particular.