Figures
- FIGURE 1
Computed tomography (CT) scan in a 60-year-old male smoker. a–c) During acute infection, mild peripheral ground-glass attenuation is present in both upper lobes, mainly in the left hemithorax (red circle). Scattered areas of cystic changes suggestive of airspace enlargement with associated fibrosis (AEF) with mild architectural distortion are present bilaterally. d–f) A CT scan performed 4 months later shows a reduction in ground-glass attenuation, with residual ground-glass attenuation and areas of AEF (f, green arrow).
- FIGURE 2
Computed tomography (CT) scan in a 62-year-old man with a–c) acute COVID infection characterised by bilateral, peripheral consolidations (b, blue arrow) and perilobular pattern (c, red arrow). d–f) A CT scan performed 2 months later shows mild peripheral reticulation and minimal perilobular pattern, mainly in the right lower lobe (f, yellow circle).
- FIGURE 3
Computed tomography (CT) scan in a 50-year-old man with a–c) COVID-related acute pneumonia with extensive, peribronchovascular consolidations in both lungs and lobular sparing in both lower lobes. Moderate ground-glass attenuation is present in both upper lobes associated with vessel enlargement (c, blue circle). d–f) A CT scan performed 2 months later shows mild, diffuse ground-glass attenuation in both lungs associated with central bronchiectasis in the middle lobe and in both lower lobes.
- FIGURE 4
a) Cluster 1. A case with a usual interstitial pneumonia pattern: architectural distortion, spatial and temporal heterogeneity of scarring modifications and microscopic honeycombing. Haematoxylin and eosin (H&E) staining ×10 magnification. b) Cluster 2. A case with morphological evidence of ongoing interstitial fibrosis and extended alveolar epithelial type II cell hyperplasia as observed in diffuse alveolar damage, proliferative phase. H&E staining. c) Cluster 2. Cytokeratin 7 immunostaining of epithelial cells, at low magnification, showing the severe effacement of parenchymal structure. d) A case with organising pneumonia pattern. H&E staining. e) Most epithelial cells and endothelial cells express nuclear phosphorylated signal transducer and activator of transcription 3. b–e ×20 magnification.
- FIGURE 5
Cluster 3. A case with diffuse vascular increase, dilatation and distortion (both capillaries and venules) within an otherwise normal parenchyma. a) Haematoxylin and eosin staining ×10 magnification, b) cytokeratin 7 immunostaining, c) diffuse and strong endothelial expression of phosphorylated signal transducer and activator of transcription 3, d) indoleamine 2, 3-dioxygenase and e) programmed cell death 1 ligand 1. b–e ×20 magnification.
Tables
- TABLE 1
Radiological and pathological findings in patients with persistent lung disease
Acute phase HRCT Post-acute phase HRCT Time from recovery (days) Histology Patient 1 Peripheral consolidation, mild crazy paving (OP-like pattern) Reticulation with some perilobular pattern, traction bronchiectasis 100 AECII hyperplasia, honeycombing, patchy fibrosis, fibroblastic foci, lymphoid nodules Patient 2 Bilateral ground glass, vessel enlargement (venoplegic hyperhemic pattern), smoking-related ILD (AEF+emphysema) Mild peripheral ground glass, smoking-related ILD (AEF+emphysema) 227 AECII hyperplasia, interstitial fibrosis, perivascular fibrosis, lymphoid nodules, macrophages containing light brown pigment Patient 3 Not performed Peripheral consolidation, ground glass, vessel enlargement (gravity-dependent perilobular pattern) 32 AECII hyperplasia, OP, vascular dilatation, perivascular fibrosis, perivascular lymphocytes, lymphoid nodules Patient 4 Peripheral consolidation, ground glass, vessel enlargement (gravity-dependent perilobular pattern) Scattered bronchial ectasis, no fibrotic distortion, mild perilobular pattern 65 OP Patient 5 Ground glass, vessel enlargement, (venoplegic/hyperhaemic pattern in a background of ILA) Stable ILA, mild ground-glass attenuation with mild perilobular pattern 76 AECII hyperplasia, perivascular lymphocytes, interstitial fibrosis Patient 6 Ground glass, vessel enlargement (venoplegic/hyperhaemic pattern) Extensive consolidations, halo sign, reverse halo sign, perilobular pattern 160 AECII hyperplasia, OP, vascular dilatation, perivascular fibrosis, perivascular lymphocytes, interstitial fibrosis Patient 7 Not performed Ground glass, vessel enlargement (venoplegic/hyperaemic pattern in a background of NSIP-OP) 56 AECII hyperplasia, perivascular lymphocytes, interstitial fibrosis Patient 8 Peripheral consolidation, ground glass, vessel enlargement (gravity-dependent perilobular pattern) Mild residual ground glass with perilobular pattern 123 Vascular dilatation, perivascular fibrosis Patient 9 Ground glass, vessel enlargement (venoplegic/hyperhaemic pattern) Mild residual ground glass with perilobular pattern 137 Minimal patchy AECII, vascular dilatation, perivascular fibrosis Patient 10 Not performed PPFE, mild ground glass 44 Vascular dilatation, perivascular fibrosis HRCT: high-resolution computed tomography; OP: organising pneumonia; AECII: alveolar epithelial type 2 cells; ILD: interstitial lung disease; AEF: airspace enlargement with fibrosis; ILA: interstitial lung abnormalities; NSIP: nonspecific interstitial pneumonia; PPFE: pleuro-parenchymal fibroelastosis.
- TABLE 2
Identification of possible subgroups (clusters) of patients with post-acute COVID-19
Clinical picture Radiological pattern Histopathology Cluster 1 Respiratory symptoms (cough, dyspnoea), no systemic symptoms, compromised DLCO Interstitial lung disease, lung fibrotic appearances with architectural distortion, traction bronchiectasis UIP or fibrosing interstitial pneumonia, spatial and temporal heterogeneity of scarring modifications, fibroblast foci, honeycombing Cluster 2 Respiratory symptoms (cough, dyspnoea), systemic symptoms (fever, fatigue), compromised DLCO Peripheral consolidation, ground glass, perilobular pattern, vessel enlargement, reverse halo sign Lung injury, OP, OP/NSIP, diffuse alveolar damage, no hyaline membranes, lymphocytic inflammatory infiltrate Cluster 3 Respiratory symptoms (cough, dyspnoea), systemic symptoms (fatigue, aches), normal DLCO Mild residual lung disease, mild ground glass, perilobular pattern Diffuse vascular increase, dilatation and distortion (capillaries and venules), otherwise normal parenchyma DLCO: diffusing capacity of the lung for carbon monoxide; UIP: usual interstitial pneumonia; OP: organising pneumonia; NSIP: nonspecific interstitial pneumonia.
Supplementary Material
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Supplementary material ERJ-02411-2021.SUPPLEMENT
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