Basic HRCT Patterns: Centrilobular Nodules

Here, our case of lymphangitic tumor will be used to demonstrate the location of centrilobular nodules, which occur in the central part of the pulmonary lobule. In this case, the nodules represent centrilobular interstitial tumor cut in cross-section.

How to Recognize Centrilobular Nodules

Look at the anterior right lung, and in your mind's eye, erase the linear structures; i.e. the thickened interlobular septa and bronchovascular interstitium (see diagrams below).

The thickened distal bronchiolovascular interstitial regions cut in cross-section remain as centrilobular nodules.



Linear, thickened bronchovascular interstitium and interlobular septa are accentuated by tumor in lymphatics. The centrilobular nodules represent lymphangitic tumor in the distal bronchiolovascular interstitium.

Here, the regularly-spaced centrilobular nodules remain when the linear structures are taken away.

Centrilobular nodules are usually of similar size and spaced at regular distances from each other. If the nodules are each at the center of a lobule, the internodular distance will be approximately 1-2.5 cm. At the periphery they occur 5-10 mm from the pleural surface (1/2 the diameter of a lobule). They usually represent linear peribronchiolar or bronchiolar densities cut in cross-section.

Centrilobular nodules most commonly occur with bronchiolar disease: lymphangitic tumor is not a common cause.



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