FIGURE 3.

Usual interstitial pneumonia (UIP) with features arguing against idiopathic pulmonary fibrosis (IPF). There are areas with established patchy interstitial fibrosis with an occasional fibroblastic focus characteristic of UIP, but also areas where interstitial chronic inflammation predominates, making this case indeterminate for UIP/IPF. Based on pathology alone, either fibrotic hypersensitivity pneumonitis or a connective tissue disease-related interstitial lung disease (interstitial pneumonia with autoimmune features) were favoured over IPF, and multidisciplinary review was recommended.