Legionnaires' disease.

Described here is a unique case of Legionnaires' disease in a previously healthy 46 year old man in whom disseminated disease was demonstrated in the kidneys, bone marrow, spleen and multiple peripheral lymph nodes at autopsy. The pathologic distribution of the lesions suggests that dissemination occurred by both hematogenous and lymphatic pathways. Pancytopenia associated with bone marrow destruction and fibrosis suggests that substances toxic to hematopoietic cells were present. It is likely that many of the unusual systemic manifestations of this disease are related to dissemination of the bacterium. The findings presented extend the spectrum of the clinical and pathologic manifestations of Legionnaires' disease from a mild and self-limited illness to a severe and fatal disseminated form of the disease.