The Multifaceted Aspects of Interstitial Lung Disease in Rheumatoid Arthritis

Table 1

Histologic and clinical classification of IIPs, applicable to RA-ILD (adapted from [29–31]).

Histologic patterns	Clinical-radiological-pathologic diagnosis
Usual interstitial pneumonia (UIP)	(Idiopathic) pulmonary fibrosis/(cryptogenic) fibrosing alveolitis (IPF/CFA)
Nonspecific interstitial pneumonia (NSIP)	Nonspecific interstitial pneumonia (NSIP)
Organizing pneumonia (OP)	Organizing pneumonia (preferred definition) = Bronchiolitis obliterans organizing pneumonia (OP = BOOP)
Diffuse alveolar damage (DAD)	Acute interstitial pneumonia (AIP)
Respiratory bronchiolitis (RB)	Respiratory bronchiolitis interstitial lung disease (RB-ILD)
Desquamative interstitial pneumonia (DIP)	Desquamative interstitial pneumonia (DIP)
Lymphoid interstitial pneumonia (LIP)	Lymphoid interstitial pneumonia (LIP)