A case of CD11b-, CD14- and CD36-positive B-cell lymphoma terminating in acute monoblastic leukemia is presented. The patient was initially suspected as having angiotrophic lymphoma due to proliferation of lymphoma cells within the sinusoid of the liver and clinical signs. Following chemotherapy, the lymphoma cells were converted into CD11b- and CD36-positive monoblasts. Lineage switching of B-cell lymphoma to acute monoblastic leukemia may have occurred in this case.