Nonspecific interstitial pneumonia NSIP

The term idiopathic interstitial pneumonias refers to a group of seven entities with distinct histologic patterns idiopathic pulmonary fibrosis (IFF), characterized by the pattern of usual interstitial pneumonia (UIP) nonspecific interstitial pneumonia (NSIP) cryptogenic organizing pneumonia (COP) respiratory bron-chiohtis-associated interstitial lung disease (RB-ILD) desquamative interstitial pneumonia (DIP) lymphoid interstitial pneumonia (LIP) and acute interstitial pneumonia (AIP). 

Fig. 26.24. A 50-year-old woman with interstitial pneumonia (lP)/nonspecific interstitial pneumonia (NSIP) after bleomycin chemotherapy for Hodgkin s lymphoma. Axial CT image shows irregular linear and reticular opacities (arrowheads) with subtle ground-glass opacities (arrow) in subpleural distribution...

The lymphoplasmacytic interstitial infiltrates seen in UIP are generally sparse in comparison to other entities such as nonspecific interstitial pneumonia (NSIP) or hypersensitivity pneumonitis (HP). Extensive cellular infiltrates or follicular lymphoid hyperplasia should lead to consideration of other entities that may cause a UIP pattern of fibrosis such as CVD or HP. Pleural inflammation is not a feature of idiopathic UIP, and its presence indicates a second process or secondary form of UIP with pleuritis, most likely a CVD such as rheumatoid arthritis (RA) or systemic lupus erythematosus (SUE) (14). 

The term nonspecific interstitial pneumonia (NSIP) was coined by Katzenstein and Fiorelli in 1994 to account for a pattern of interstitial fibrosis that appeared to have distinct features from UIP. Notably, it was observed that in some patients the interstitial process was more cellular than was typical for UIP and the characteristic features of spatial and temporal heterogeneity were not seen. Therefore, a new term, NSIP, was introduced (19). 

Since corticosteroid therapy has no effect on the nonspecific interstitial pneumonia (NSIP) that usually characterizes SSc ILD, identification of COP becomes important. Although still controversial, corticosteroids are usually avoided in SSc for fear of precipitating SSc renal crisis (51). Whether corticosteroids will precipitate an SSc renal crisis now that patients with diffuse SSc are treated prophylactically with an angiotensin converting enzyme (ACE) inhibitor remains unknown. 

Abbreviations HRCT, high-resolution computed tomography NSIP, nonspecific interstitial pneumonia. 

Figure 2 (See color insert.) Nonspecific interstitial pneumonia. (A) NSIP fibrotic pattern interstitial fibrosis in a temporally and spatially homogeneous pattern (original magnification, 20x Masson s trichrome stain). (B) NSIP cellular pattern interstitial lymphocytic infiltrates in a temporally and spatially homogeneous pattern (original magnification, 40 x H E stain). (C) NSIP fibrotic pattern interstitial fibrosis in a temporally and spatially homogeneous pattern (original magnification, 200x H E stain). Abbreviation-. NSIP, nonspecific interstitial pneumonia.

Figure 1 HRTC scan from a 52-year-old female with NSIP. (A) The upper and (B) lower lobes demonstrate mild GGO. Reticular thickening is also present in the right lower lobe. Abbreviations HRCT, high-resolution computed tomography NSIP, nonspecific interstitial pneumonia GGO, ground-glass opacities.

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