抄録
A 53-year-old male with primary myelofibrosis was reported. He had dizziness of 8 months' duration and was found on physical examination to have anemia and hepatomegaly of 3 fingerbreadths and splenomegaly of 5 fingerbreadths. No lymphadenopathy was found. Laboratory findings were as follows: peripheral RBC 264×104/cmm, Hb 51%, WBC (nucleated cell count) 27,200, leucocyte alkaline phosphatase score 315. In peripheral blood smear, nucleated red blood cells occupied 55% of nucleated cells. Tear drop poikilocytosis of red blood cells was negative. Serum Vitamin B12 level was very high with the value of 2760 pg/ml. Ph1 chromosome was negative. Ferrokinetic study with 59Fe was suggestive of ineffective erythropoiesis. Bone marrow punctures on sternum were hardly successful and biopsy was done on pelvic bone, revealing fibrosis of the bone marrow. When the biopsy of the liver was made, the patient died of bleeding accident. Autopsy was performed and revealed various degrees of bone marrow fibrosis. Spleen weighed 1580 g with remarkable extramedullary hematopoiesis. No leukemic infiltrations were found.
In this case differential diagnosis between erythremia and myelofibrosis was difficult by peripheral blood smear alone because of high percentage of nucleated red cells. It has been said that vitamin B12 level is a useful means to differentiate myelofibrosis and chronic myelogeneous leukemia. It was inconvenient, however, to use the data of the Vitamin B12 determination in differential diagnosis of the present case. It implies that concept of myloproliferative syndrome should be appropriate in considering the nature of myelofibrosis.
