Idiopathic Interstitial Pneumonia

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Idiopathic Interstitial Pneumonia

The term idiopathic interstitial pneumonia (IIP) is applied to a group of disorders with distinct histologic and radiologic appearances and without a known cause. These disorders are tabulated in Table 56.1.

The histologic temporal and spatial heterogeneity of usual interstitial pneumonia (UIP) results in characteristic constellation of basal-predominant, peripheral-predominant reticular abnormality and honeycombing. Nonspecific interstitial pneumonia (NSIP), desquamative interstitial pneumonia (DIP), acute interstitial pneumonia (AIP), and lymphoid interstitial pneumonia (LIP) are microscopically homogeneous and are characterized by homogeneous attenuation at thin-section computed tomography (CT).