Crossing the lung fissures
Only a small number of pulmonary diseases are known to directly cross the lung fissures such that the lung pathology extends from one lobe via the interlobar fissure into an adjacent lobe . The finding is most commonly due to primary malignancy, however, some infections are also known to do so.
Terminology
A bulging fissure is different as this entity is due to mass effect on the fissure but there is no suggestion that the pathology in question has transversed the fissure so that it is now in two adjacent lobes.
Differential diagnosis
- infection
- malignancy: tumor infiltration of the lung fissures has been described for many lung cancers and lymphoma
Practical points
Occasionally the synchronous presence of opacity in two adjacent lobes may incorrectly lead to the presumption that the pathology directly crossed through a fissure but in fact, the infection/malignancy reached both lobes through normal routes, most commonly the airways.
Occasionally due to absence of part or all of an interlobar fissure, a lung pathology will be erroneously assumed to have crossed a fissure, when no such infiltration actually occurred.
