Inflammatory pseudotumor of the liver associated with acute myelomonocytic leukemia. A patient with inflammatory pseudotumor of the liver associated with acute myelomonocytic leukemia (M4) is reported. He had spiking fever, epigastralgia, and elevated levels of serum C-reactive protein (CRP) and alkaline phosphatase (ALP). Ultrasonography showed a hypoechoic mass in the liver, and ultrasonically guided fine needle aspiration biopsy of the mass revealed that it was composed of fibrous connective tissue infiltrated with plasma cells, eosinophils, and neutrophils. Accordingly, a diagnosis of inflammatory pseudotumor of the liver was made. Marked reduction in the size of the lesion and a decrease of the levels of the CRP and ALP occurred without specific treatment. We emphasize the importance of ultrasonically guided aspiration biopsy in diagnosis of inflammatory pseudotumor of the liver without the need for surgery. 