Figure 1: Histopathological features of lung biopsies submitted for the evaluation of EVALI.
Lung biopsies submitted to the CDC were characterised on the basis of patterns of acute lung injury on haematoxylin and eosin stained slides. (A) Case 3 showed features of exudative and proliferative diffuse alveolar damage, with prominent hyaline membranes (arrow; 10× magnification). (B) Clusters of foamy macrophages (asterisk) were present in all ten biopsy lung samples and were abundant in case 5 (shown); type II pneumocyte hyperplasia was also prominent in case 5 (arrow; 40× magnification). (C) Features of proliferative and organising diffuse alveolar damage were seen in case 10, including type II pneumocyte hyperplasia (arrow) and fibroblastic proliferations (asterisk; 10× magnification). (D) Fibroblastic proliferations within airways and alveoli (asterisks), consistent with organising pneumonia, were a notable feature in case 7 (10× magnification). (E) Airway-centred inflammation and intrabronchiolar fibroblastic plugs (asterisks), consistent with organising pneumonia, were seen in case (4·5× magnification). (F) Higher magnification of figure 1E (case 4) showing fibroblastic plugs infiltrated by eosinophils and macrophages (40× magnification). CDC=Centers for Disease Control and Prevention. EVALI=e-cigarette, or vaping, product use-associated lung injury.