On day 9, pathology reported alveolar tissue with patchy chronic inflammation, type 2 pneumocyte hyperplasia, and areas of organising intra-alveolar fibrin and fibroblastic tissue, consistent with acute lung injury. No hyaline membranes, viral cytopathic changes, giant cells, granulomas, or malignancy were present, and no microorganisms were identified on acid-fast or Grocott's methenamine silver staining (figure 2A ). Cytological examination of the BAL found marked reactive changes in pneumocytes, with lymphocytes, histiocytes, and occasional fibroblastic balls lined by pneumocytes, with negative Grocott's methenamine silver staining (figure 2B). RT-PCR for SARS-CoV-2 of the BAL specimen was positive; BAL and serum galactomannan were negative. No additional antibiotic or prednisone was given. On day 10, the patient declined treatment with hydroxychloroquine and was discharged home. Via follow-up phone calls, the patient reported that his cough and myalgias slowly resolved, and he had no fever higher than 37·8°C after discharge. No chest imaging was done after discharge.
Figure 2 Pathology of transbronchial biopsy and BAL cytology
(A) Transbronchial biopsy showing prominent pneumocyte hyperplasia with areas of organising fibrin and fibroblastic tissue. The alveolar septa showed some mild chronic inflammatory cell infiltrates (haematoxylin-eosin stain, original magnification × 200). (B) BAL cytology specimen showing a fibroblastic ball lined by pneumocytes (Papanicolaou stain, original magnification × 400). BAL=bronchoalveolar lavage.