Perifissural lung nodules

Perifissural lung nodules (PFNs) are a type of intrapulmonary nodule that, most of the time, represent pulmonary lymph nodes. 

Terminology 

Although perilymphatic pulmonary nodules can also be perifissural in distribution, they should be distinguished from perifissural lung nodules, as the former are usually associated with a number of conditions.

Radiographic features

CT

Perifissural lung nodules 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 perifissural lung nodules have typical morphology they are favored to be benign despite some nodules having a tendency to grow over serial scans ².