Review Article

The Multifaceted Aspects of Interstitial Lung Disease in Rheumatoid Arthritis

Table 2

Histological and radiological patterns of RA-ILD [9, 10, 2931].

PatternHistologyCT featuresCT differential diagnosis

UIPSubpleural and peripheral fibrosis. Fibroblastic foci, lymphoid aggregates with germinal centres and honeycombing are characteristic. Mild inflammation; architectural destruction.Peripheral, subpleural, basal reticulation, and honeycombing  
Traction bronchiectasis, architectural distorsion, GGO (less diffuse). Subpleural lines
IPF, other collagen vascular diseases, hypersensitivity pneumonitis (micronodules and sparing of lung bases), sarcoidosis, asbestosis (pleural thickening).

NSIPUniform interstitial involvement; various degrees of fibrosis and/or inflammation. Lymphoid aggregates. Rare honeycombingBilateral, symmetrical, patchy, mainly basal GGO,  possible reticulation, traction bronchiectasis, irregular lines, or consolidation. Little or no honeycombing (in fibrosing NSIP).UIP, DIP, COP, hypersensitivity pneumonitis, and HIV-associated interstitial lung disease.

OPConnective tissue plugs within small airways and air spaces (Masson bodies). Little or no inflammation or fibrosis.Patchy and multiple airspace consolidation, mainly basal, peripheral, or peribronchovascular. Air bronchograms can be seen. Possible associated GGO or centrilobular nodules.Infections, vasculitis, sarcoidosis, alveolar carcinoma, lymphoma, eosinophilic pneumonia, NSIP, and COP.

DAD(i) Acute phase: hyaline membranes, edema.
(ii) Organizing phase: airspace and interstitial organization
(i) Acute phase: progressive, patchy, or diffuse GGO and dependent  consolidation, often with lobular sparing
(ii) Organizing phase: reticulation, traction bronchiectasis, and architectural distorsion.
Hydrostatic edema, pneumonia, eosinophilic pneumonia, and ARDS (but more symmetrical and lower lung zones)

DIPExtensive macrophage accumulation in the distal air spaces. Mild interstitial involvement. Patchy GGO, basal, and peripheral. Microcystic changes within GGO, reticular lines. RB-ILD, hypersensitivity pneumonitis, sarcoidosis, and Pneumocystis jiroveci pneumonia.

RB-ILDBronchiolocentric macrophage accumulation. Mild bronchiolar fibrosisDiffuse/upper lobes distribution, centrilobular nodules, bronchial wall thickening, and patchy GGO.DIP, NSIP, and hypersensitivity pneumonitis

LIPBronchiolocentric lymphoid tissue hyperplasiaDiffuse, GGO, centrilobular nodules, septal and bronchovascular thickening, thin-walled cysts, and lymph node enlargement.Sarcoidosis, lympangitic carcinoma, and Langherans’ cell histiocytosis

GGO: ground glass opacities; UIP: usual interstitial pneumonia, NSIP: non-specific interstitial pneumonia, OP: organizing pneumonia; COP: cryptogenic organizing pneumonia; DAD: diffuse alveolar damage; DIP: desqumative interstitial pneumonia; RB-ILD: respiratory bronchiolitis-associated interstitial lung disease; LIP: lymphoid interstitial pneumonia; IPF: idiopathic pulmonary fibrosis.