CHRONIC ERYTHROMONOCYTIC LEUKEMIA

Three cases are presented which demonstrate an association between refractory sideroblastic anemia and chronic monocytic leukemia. The cases are characterized from the point of view of the anemia by ineffective erythropoiesis, a hyperplastic erythroid bone marrow showing megaloblastoid changes, and numerous ringed sideroblasts and hypochromic microcytic red cells. The white cell changes in the peripheral blood are an absolute monocytosis with mature, but somewhat atypical, monocytes and in the bone marrow a slow but progressive increase in monocytic cells. Serum muramidase levels are increased. The course is prolonged and relatively benign except for the anemia. These cases seem to be at the benign end of a spectrum of neoplastic diseases involving the monocytic and erythrocytic series simultaneously. More malignant cases are characterized by more severe anemia, granulocytopenia and thrombocytopenia as a prodromal phase of a terminal acute blastic leukemia. The most malignant form is that in which acute erythroblastic and monoblastic proliferation occur as the presenting and terminal event. © 1969.