Metabolic and storage lung diseases: spectrum of imaging appearances

Metabolic and storage diseases constitute a heterogeneous group of disorders that occur in the setting of altered biochemical homeostasis. Many of these disorders affect the lungs, either exclusively or as part of a systemic syndrome. For example, amyloidosis can be limited to the tracheobronchial tree or involve the kidneys, lungs and heart. The indolent course of some of these disorders and the non-specific clinical symptoms often result in a diagnostic challenge. Imaging, particularly high-resolution computed tomography (HRCT), is an invaluable asset in the diagnosis of these clinical conditions. Some metabolic and storage diseases have characteristic HRCT appearances, helping narrow the differential diagnosis. Correlation of the radiological and histopathological findings of this group of diseases has also helped improve understanding of these disorders. In addition, CT can offer guidance when tissue sampling is warranted and aid in histopathological diagnosis. This article describes the pertinent clinical features of the more common metabolic and storage diseases affecting the lungs, illustrates their respective HRCT findings and provides the relevant differential diagnosis. • To recognise the various metabolic and storage lung diseases; • To identify the characteristic imaging findings in various metabolic and storage lung diseases; • To discuss the relevant differential diagnoses of each of these diseases.