We experienced an autopsy case of who was discovered in a state of cardiopulmonary arrest and subsequently declared deceased due to severe pneumonia. Tests using a pan bacterial/viral detection kit and qualitative polymerase chain reaction (PCR) for Legionella pneumophila were negative. However, using deoxyribonucleic acid extracted from formalin-fixed paraffin-embedded lung tissue, PCR amplification of the ssrA gene of congeneric Legionella species yielded positive results. Histologically, slight staining was observed in the cytoplasm of macrophages in lung alveoli by Warthin-starry and Gimenez stains.

In this study, our data reveal that the degranulation in direct fast scarlet (DFS) staining allows us to distinguish eosinophilic colitis (EC) and control in both right and left hemi-colons. According to the current standard to diagnose EC (count by HE staining ≥20 cells/HPF), mucosal sampling from left hemi-colon is problematic since the number of eosinophils could not be increased even in EC. Determination of degranulated eosinophils by DFS may potentiate the diagnostic performance even in such conditions.