Abstract
A 23-year-old male patient with plasma cell leukemia showed characteristic clinical features: accelerating heart failure and consciousness disturbance accompanied with an increase of plasma cells in peripheral blood. Evaluation of cardiac function revealed a hyperdynamic cardiac state with low somatic vascular resistance, indicating high-output cardiac failure. However no disorders causing high-output cardiac failure were found. Consciousness disturbance and hyperammonemia with serum amino acid abnormality of unknown origin were also demonstrated. After intensive combined chemotherapy (MVD+VAD), high-output cardiac failure and hyperammonemia improved with disappearance of plasma cells, suggesting that these symptoms were closely related with progression of plasma cell leukemia.