Imaging description

Lymphangitic carcinomatosis typically affects the central (perihilar) and peripheral lymphatic system of the lung [1]. Centrally there is thickening along the arteries and bronchi (i.e., peribronchovascular interstitium) (Figure 74.1). Peripherally there is thickening of the interlobular septa. This smooth thickening can be a result of either tumor or edema due to lymphatic obstruction. Less common, but more specific is nodular or beaded thickening of these spaces [1, 2] (Figure 74.2). On CT, hilar or mediastinal lymph node enlargement is present in approximately 40% of cases and pleural effusion in 30% [3]. Lung involvement may be bilateral (Figure 74.2), but is found to be asymmetrical (Figure 74.3) or unilateral in approximately 50% [3]. Unilateral involvement is most often caused by bronchogenic carcinoma [3] (Figure 74.1). Additional findings may include hematogenous metastatic disease (Figure 74.3) or identification of the primary tumor.

Importance

Lymphangitic carcinomatosis is a common presentation of metastatic disease in the chest. The presentation of nodular interlobular septal thickening can be diagnostic.