1986 Volume 27 Issue 5 Pages 747-751
A 46-year-old man was referred to Nippon Kokan hospital in July 1981 for dizziness. Physical examination showed severe anemia but no splenomegaly or lymphadenopathly. Blood examinations on admission revealed WBC 1,600/μl, RBC 133×104/μl, Hb 4.0 g/dl, and Plts 2.6×104/μl. Bone marrow biopsy showed marked fibrosis and atypical megakaryocyts. He remained well until March 1982, when he was readmitted because of progressive anemia with 19% of blasts in the peripheral blood. These blasts were identified in megakaryoblast as they were positive for electron microscopic platelet peroxidase. These findings were compatible with acute megakaryoblastic leukemia (acute myelofibrosis). The paient died of pneumonia in June 1982. Appearance of monoclonal gammopathy (IgG λ) and a few plasma cells in peripharal blood in the terminal stage, and marked nodular proliferation of plasma cells including some atypical form of in the spleen and bone marrow at autopsy suggest neoplastic change of plasma cells. It is of interest that co-existence of acute megakaryoblastic leukemia (acute myelofibrosis) and plasma cell malignancy may be due to neoplastic change in the stage of pluripotent hemopoietic stem cells.
