Sarcoidosis

Imaging description Pulmonary sarcoidosis is characterized by nodules in a perilymphatic distribution on CT imaging [1–3]. A perilymphatic distribution indicates that the findings are seen along the bronchovascular bundles, the interlobular septa, and along the pleural surfaces [1] (Figures 10.1–10.4). In sarcoidosis, the nodules tend to have a perihilar predominance as well. The nodules may coalesce to form conglomerate masses which result in architectural distortion of the lung. Adenopathy may also be present depending on the stage of the disease (Figure 10.4). Calcification is often present in the nodes and is often amorphous, but can rarely be peripheral (egg-shell). Areas of air trapping can be seen on expiratory imaging in the majority of cases [1]. Additional presentations of pulmonary sarcoidosis include consolidation, cavitation, and fibrosis, but these are less common. Importance Sarcoidosis is a systemic granulomatous disease of unknown etiology that commonly affects the lungs. It typically occurs in young adults, but can be seen in older individuals as well [3]. In the appropriate clinical setting, the imaging findings on CT can be diagnostic.