On HRCT thorax, which of the following findings is MOST characteristic of lymphangitic carcinomatosis and helps distinguish it from pulmonary oedema?

• A Smooth interlobular septal thickening
• B Bilateral pleural effusions with perihilar ground-glass opacity
• C Centrilobular nodules with tree-in-bud pattern
• D Nodular (beaded) interlobular septal thickening with preserved lung architecture ✓

Explanation

Lymphangitic carcinomatosis produces nodular or beaded thickening of interlobular septa (irregular septal thickening) and the bronchovascular bundles, with preservation of overall lung architecture. Pulmonary oedema causes smooth septal thickening (Kerley B lines) with bilateral effusions. Tree-in-bud pattern indicates endobronchial spread or infection. The nodular beading reflects tumour cells within lymphatics.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.