"Non-specific interstitial pneumonia (NSIP) is the second most common morphological and pathological pattern of interstitial lung disease after UIP. NSIP is commonly associated with connective tissue disease (CTD), and a multidisciplinary team is best suited to determine the underlying diagnosis and management 12,17."
"The NSIP pattern often evolves into a UIP pattern over time 11,18. Evaluation of prior CT scans is essential for correct categorisation 18."
"In general, NSIP carries a much more favourable prognosis than UIP, with an overall 5-year survival of ~80% for idiopathic NSIP 19 and a nearly 100% 5-year survival rate for the cellular subtype and a ~60% (range 45-90%) 5-year survival rate for the fibrotic subtype 12. Cellular NSIP shows a better response to corticosteroids and carries a substantially better prognosis than the fibrotic type. Correct and early diagnosis has a significant impact on patient outcomes because NSIP usually responds well to corticosteroid therapy or cessation of inciting causes, e.g. drugs or organic allergens 12. Mycophenolate mofetil has also been shown to improve lung function 15."
"Temporal and spatial homogeneity in a specimen is an essential feature 12,21. Historically, non-specific interstitial pneumonia was divided into three groups; however, due to similar outcomes, groups II and III (mixed cellular and fibrotic and mostly fibrotic, respectively) are now both classified as fibrotic type 12:"
"tends to be a dominant feature (~90%; range 76-100%): can be symmetrically or diffusely distributed in all zones or display a basal predominance 1,12,23"
"Important negative histological findings include the absence of acute lung injury (hyaline membranes, granulomas, organisms, or viral inclusions), dominant airways disease or organising pneumonia, eosinophils, and coarse fibrosis 12."
"immunoglobulin G4 (IgG4)-related sclerosing disease, with or without overlapping features with Rosai-Dorfman disease 13"