Organizing pneumonia: the many morphological faces.

Organizing pneumonia is a non-specific response to various forms of lung injury and is the pathological hallmark of the distinct clinical entity termed cryptogenic organizing pneumonia. The typical imaging features of this syndrome have been widely documented and consist of patchy air-space consolidation, often subpleural, with or without ground-glass opacities. The purpose of this article is to highlight the less familiar imaging patterns of organizing pneumonia which include focal organizing pneumonia, a variety of nodular patterns, a bronchocentric distribution, band-like opacities, a perilobular pattern and a progressive fibrotic form of organizing pneumonia.