Although perilymphatic pulmonary nodules can also be perifissural in distribution, they should be distinguished from PFNs, as they are usually associated with a number of conditions.
PFNs are typically seen as well-circumscribed, smoothly marginated homogeneous nodules in contact with or closely related to a pulmonary fissure. Most show a triangular, oval/lentiform, rectangular, or dumbbell shape. They may often show a septal attachment to the pleural surface 3.
Worrisome features that are not typical for lymph nodes and should be reported, prompting for imaging follow-up, include 6:
- round morphology or contour irregularity
- the adjacent fissure is abnormal: bowed, retracted, or transgressed
Treatment and prognosis
If they have typical morphology they are favoured to be benign despite some nodules having a tendency to grow over serial scans 2.
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