Sarcoidosis is characterized by non necrotizing granulomas distributed along the lymphatic pathways of broncho vascular bundles and interlobular septa. The opacities tend to be nodular and predominate in upper and mid zones.

The nodules are often clustered in hilar and peribroncho-vascular region, with relative sparing of the lung periphery.

In late stages , cicatrical changes cause architectural distortion and fibrotic areas of consolidation. Sarcoidosis may be difficult to differentiate from lymphangitis carcinomatosis because both have lymphadenopathy and peribroncho-vascular nodules and septal thickening. Cicatrical changes with traction bronchiectasis help to differentiate the two. Also , the nodules are more in sarcoidosis than in lymphangitis carcinomatosis.