Severe bleeding tendency caused by leukemic infiltration and destruction of vascular walls in chronic neutrophilic leukemia.

Bleeding is reportedly one of the major causes of death in patients with chronic neutrophilic leukemia (CNL), but thrombocytopenia, abnormal platelet functions, or coagulopathy has been confirmed to be the cause of the bleeding tendency in only a small proportion of the patients. We report the case of a 49-year-old woman with CNL who experienced episodes of cutaneous and recurrent multiple cerebral hemorrhages without severe thrombocytopenia, detectable abnormal platelet functions, or coagulating dysfunction. Histological examination of specimens obtained at autopsy showed extensive infiltration and destruction of vascular walls by leukemic cells, which could explain her severe bleeding tendency. This study is the first to clearly show that the infiltration and destruction of vascular walls by leukemic cells can cause fatal bleeding episodes without warning from laboratory findings. Further studies are needed to elucidate the mechanism of the infiltration and destruction of blood vessels by CNL cells and to develop effective measures to control the growth and infiltration of CNL cells.