Chronic Myelomonocytic Leukemiaの1症例

抄録

A 69 year old male was admitted to our hospital because of the symptoms of low grade fever, cough and bloody sputum. Physical examination revealed moist rales in the left pulmonary field, dilated veins in the lower abdomen and hepatic enlargement without splenomegaly. A chest X-ray film showed a shadow of chronic bronchitis complicated with bronchiectasia. The hematological examination revealed a moderate anemia with 9.6 g/dl hemoglobin concentration, 299×10⁴/cmm red blood cell count, 18×10⁴/cmm platelet count, and mild leucopenia of 3,800/cmm leucocyte count with 56% of abnormal monocytes or monocytoid cells on peripheral blood smear. Neutrophil alkaline-phosphatase score was 62 (normal 240±60). These monocytes or monocytoid cells were relatively large with poor basophilic cytoplasma and distinct nucleolus in the nucleus. Histochemical studies of these cells showed the characters of monocytes with positive peroxidase, acid phosphatase, alpha-naphthyl acetate esterase, naphthol AS-D chloroacetate esterase, phagocytosis and negative alkaline phosphatase. However, in his bone marrow, only 2.8% of monocytes or monocytoid cells were counted. The nucleated bone marrow cell count was 26.3×10⁴/cmm, and a marked hyperplasia in the granulocytic series was noted with no Auer body and negative Ph¹ chromosome. From these clinical and laboratory findings, this case was diagnosed as the so called chronic myelomonocytic leukemia. This case was suggested to be a valuable case for the clarification of the pathogenesis of leukemia and the mechanism of monocyte and granulocyte differentiation, since evidences showing the presence of the common comimtted myeloid stem cell were abundantly demonstrated in recent studies.