[Three cases of necrotizing pneumonia by pseudomonas aeruginosa infection in hematological malignancy, including dead and alive cases].

Pseudomonas aeruginosa (P. aeruginosa) is a common nosocomial pathogen that often causes pneumonia, especially in immunocompromised patients including cancer bearing-hosts. In cancer patients who have great risk of gram-negative bacteria leading to fatal infection, P. aeruginosa bacteremia easily results in septicemia with shock and life-threatening complications such as vital organ failure. Among those complications, necrotizing pneumonia is an infectious disease of lung caused by P. aeruginosa characterized by rapid cavitation and progressive clinical course, which is fatal not only in cancer patients but also in healthy hosts. P.aeruginosa is one of the pathogens targeted for empirical therapy neutropenic patients. Three case series of necrotizing pneumonia were reviewed in this report. All three had hematological malignancies and were immunocompromised. One of the three cases,a 30-year-old man with malignant lymphoma, recovered from pneumothorax and pyothorax complicated with lung cavitation. The other two patients died with a short course; a 55-year-old man with chronic myelogeneous leukemia within 7 hours, and a 54-year-old man with malignant lymphoma within 2 days after the onset of pneumonia, respectively. In these 3 cases, there were no obvious associations between prognosis and neutrophil counts, duration of neutropenia and steroid administration.