Nodular and Smooth Thickening of Interlobular Septa vs Hydrostatic Pulmonary Edema

Figure 1. Nodular Thickening of Interlobular Septa


Nodular thickening of interlobular septa is seen in the right lung, especially posteriorly.

The unusual appearance of architectural distortion here is due to the fact that the malignancy in this case was mesothelioma, and this tumor is well known to produce distortion and volume loss in the affected hemithorax.

Find an example of nodular thickening of septa in the right lower lobe.

The left lung is essentially normal.

Figure 2. Smooth Thickening of Interlobular Septa

Smooth thickening of septal lines is present in the right lung, and the secondary lobule takes on a polygonal configuration, which is characteristic of PLC. Note the bronchiolovascular bundle seen as a dot within the center of many of the polygons.

Note the presence of bronchovascular thickening in the right lower lobe, as well as the right pleural effusion.

Click here to return to the HRCT image of Unknown 10 to identify the "polygon and dot" pattern. Click here for a diagram of the "polygon and dot" pattern. Remember to use the "back" button in the menu bar to return.

Figure 3. Hydrostatic Pulmonary Edema

This image shows hydrostatic pulmonary edema, an important consideration in the differential diagnosis of lymphatic carcinomatosis with smooth interlobular septal thickening.

The diagnosis of hydrostatic edema was confirmed by resolution of the scan findings following diuresis.

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Nodular thickening of interlobular septa