| HE staining | Respiratory epithelium，a small number of phagocytes and neutrophils，and scattered red staining without structures were seen in lavage fluid sediment |
| IHC staining | PE-10（+），TTF-1（+，partially），Napsin-A（+） |
| Special staining | PAS（+），PAS-D（+） |
| TEM | Few red staining without structures were observed in the sediment of lavage fluid sediment，and osmiophilic multilamellar bodies（OMBs）were observed under TEM in lavage fluid rather than sputum or induced sputum |
| Pathological diagnosis | The diagnosis of pulmonary alveolar proteinosis（PAP）was made according to the results of imaging，IHC staining，special staining and TEM |
