UIP Pattern

The criteria that allow a diagnosis of definite UIP include reticular abnormality and honeycombing with a subpleural, basal predominance.5 Importantly, there should be an absence of exclusionary features such as micronodules, cysts, mosaic attenuation and air trapping, and consolidation.5 Here we see significant honeycombing, which can be seen in a predominantly subpleural pattern occurring at the bases of the lung as seen in the coronal image. Peripheral reticulation and traction bronchiectasis are present, with an absence of the noted exclusionary features. Note the asymmetric pattern of fibrosis, a hallmark feature of usual interstitial pneumonia not often seen with NSIP.5