Micronodular Lung Disease

Micronodular lung disease may occur secondary to a large number of pulmonary disorders. A systematic approach when interpreting a chest CT scan showing multiple micronodules can significantly narrow the differential diagnosis. This article describes the imaging characteristics of micronodular lung disease, with a structure organized according to the prevalent distribution of micronodular opacities relative to the secondary pulmonary lobule. While the large number of disorders that can cause a micronodular pattern prevents a thorough discussion of all conditions, this article reviews the most relevant diseases associated with each pattern, with particular attention to imaging findings useful for differential diagnosis.