COP | Idiopathic NSIP | IPF | |
Histopathological pattern | Organising pneumonia | NSIP | Usual interstitial pneumonia |
Histopathological features | Preserved lung architecture, intralumenal buds of granulation tissue in the distal airspaces (alveoli and alveolar ducts, possibly bronchioles); mild interstitial chronic inflammation; patchy distribution | Temporal and spatial homogeneity,mild-to-moderate interstitial inflammation (usually lymphocytic) with intra-alveolar organising fibrosis (minor component) and lack of interstitial fibrosis (cellular NSIP pattern); dense or loose interstitial fibrosis with mild or moderate interstitial chronic inflammation (fibrosing NSIP pattern) | Architectural destruction; temporal and spatial heterogeneity (areas of normal lung present); interstitial fibrosis with honeycombing; fibroblastic foci |
Mean age yrs | 50–60 | 40–50 | 60–70 |
Onset | Subacute | Chronic/subacute | Chronic |
Clinical manifestations | Mild dyspnoea, cough, fever, sparse crackles; no finger clubbing | Moderate-to-severe dyspnoea, cough; diffuse crackles; finger clubbing uncommon | Severe dyspnoea, cough; severe restrictive ventilatory defect at lung function tests, with marked hypoxaemia; diffuse crackles; finger clubbing common |
Imaging features# | Patchy areas of consolidation (peripheral, bilateral, possibly migratory, air bronchogram) | Ground-glass opacities and reticulation, basal predominance | Reticular abnormalities, honeycombing, traction bronchiectasis (peripheral, basal) |
BAL | Mixed pattern (mild increase in lymphocytes, neutrophils, eosinophils) | Increase in lymphocytes (and possibly neutrophils) | Increase in neutrophils (and possibly eosinophils) |
Prognosis | Excellent without sequelae | Very good (cellular pattern); rather poor (fibrosing pattern) | Poor |
Response to corticosteroid treatment | Excellent | Usually good (cellular pattern);usually moderate or poor (fibrosing pattern) | Poor |
BAL: bronchoalveolar lavage. #: high-resolution computed tomography.