Smooth or nodular interlobular septal thickening with thickened bronchovascular bundles and preserved lung architecture, often unilateral or asymmetric, in a patient with cancer — separate it from pulmonary oedema, which is smooth, bilateral and resolves.
Orient first
- Tumour in the lymphatics: breast, lung, stomach, pancreas, prostate.
- Nodular (beaded) septal thickening is characteristic; smooth thickening overlaps with oedema.
- Effusions and hilar nodes are common.
Acquire the study
- High-resolution CT chest with thin sections; contrast for nodes.
The manoeuvre
- Lung window: interlobular septal thickening — smooth vs beaded — and its distribution (often asymmetric).
- Peribronchovascular interstitial thickening and fissural nodularity.
- Polygonal arcades with a central dot on axial slices.
- Hilar and mediastinal nodes; pleural effusion.
What confirms it
- Nodular septal thickening in a patient with a known malignancy.
What licenses you to exclude it
- Symmetric smooth septal thickening with cardiomegaly that resolves with diuresis is oedema.
The classic misread
- Calling it oedema in a patient with breast cancer and a unilateral pattern.