Hypocellular bone marrow with increased blasts

Abstract Twenty patients with hypocellular bone marrow and increased blasts (HBMIB) were reviewed. The median age was 60 years with a male:female ratio of 17: 3. History of alcohol abuse was noted in 30%, potential exposure to toxic chemicals in 20%, second malignancies in 20%, and aplastic anemia in 25%. Pancytopenia with marrow hypocellularity and increased marrow blast cells were characteristic hematopathologic features. Marrow hypocellularity was moderate to severe (>25%) in over half of the cases and mild to moderate (>25, >35%) in the remainder. Blast cells were the predominant cellular elements in the marrow displaying scanty to moderate amounts of cytoplasm, round to oval nuclei, and one or more nucleoli. Special stains were performed in 19 cases. Blast cells morphologically displayed myeloid features, but Sudan black B and/or peroxidase positivity was noted in only ten patients. The overall mortality was high, especially in patients undergoing chemotherapy. At 1 year follow‐up, 11 patients had received chemotherapy and eight of these eleven were dead compared to three of nine patients dead in those not receiving chemotherapy. Only two patients developed „overt” leukemia evidenced by hypercellular marrow and over 30% blast cells in the peripheral blood. HBMIB is a distinct clinicopathologic entity characterized by severe marrow failure and a low response rate to chemotherapy.