Acute megakaryoblastic leukemia with increased hematogones in children.

We describe 2 patients, a 4-month-old male and a 17-month-old female, with de novo acute megakaryoblastic leukemia with increased number of hematogones at diagnosis. Both children were admitted in the hospital with thrombocytopenia. The bone marrow smears in the first child revealed the presence of 60% cells with morphologic features consistent with acute megakaryoblastic leukemia. In the other, the initial bone marrow aspirate was dry tap but on the following aspirate 10% cells with lymphoblastic morphology could be seen. The bone marrow flow cytometry showed the presence of hematogones-38% in the first case and 20% in the second-with absence of blasts. Repeated bone marrow aspirates, trephines, and immunophenotypic as well as molecular studies, confirmed the diagnosis of M7. Both children were treated according to the Berlin-Frankfurt-Munster 2004 protocol.

Bacterial meningitis from Rothia mucilaginosa in patients with malignancy or undergoing hematopoietic stem cell transplantation.

Opportunistic infections contribute to morbidity and mortality of patients undergoing hematopoietic stem cell transplantation and treatment for malignancies. Rothia mucilaginosa, a gram-positive bacterium, is responsible for rare, but often fatal meningitis in severely immunocompromised patients. We describe two cases of meningitis from discrete strains of R. mucilaginosa on our pediatric bone marrow transplant unit, summarize the published cases of R. mucilaginosa meningitis in oncology and stem cell transplant patients, and provide updated recommendations regarding the use of antibiotic therapy in this patient population.

Hematopoietic stem cell transplantation for de novo acute megakaryocytic leukemia in first complete remission: a retrospective study of the European Group for Blood and Marrow Transplantation (EBMT).

Acute megakaryoblastic leukemia (M7 AML) is a highly aggressive disease. We evaluated outcomes in 57 children (11 with Down syndrome) and 69 adults with M7 AML after first complete remission (CR1) following autologous or HLA-identical allogeneic transplantation. Characteristics of the recipients of autologous transplants (38 children, 37 adults) were, respectively: median age, 1.7 and 46 years; non-total body irradiation (non-TBI) conditioning regimen, 97% and 70%; bone marrow as stem cell source, 74% and 43%. Characteristics of the recipients of allogeneic transplants (19 children, 32 adults) were, respectively: median age, 2.8 and 37 years; non-TBI regimen, 63% and 42%; bone marrow as stem cell source, 95% and 69%. Autologous transplantation benefited children more; the relapse rate was high in adults. Results for autologous transplantation were (children and adults, respectively): engraftment, 90% and 100%; 3-year treatment-related mortality (TRM) rate, 3% and 8%; relapse rate, 45% and 64%; leukemia-free survival (LFS) rate, 52% and 27%; overall survival (OS) rate, 61% and 30%. After allogeneic transplantation, TRM was fairly low in children and adults, and relapse rates were lower than after autologous transplantation. Results for allogeneic transplantation were, respectively: engraftment, 95% and 90%; TRM, 0% and 26%; relapse rate, 34% and 28%; LFS, 66% and 46%; OS, 82% and 43%). We conclude that M7 AML patients in CR1 (except children with Down syndrome, who already have better outcomes) can benefit from transplantation.

Acute megakaryoblastic leukemia with massive myelofibrosis: complete remission and reversal of marrow fibrosis with allogeneic bone marrow transplantation as the only treatment.

We report results of allogeneic bone marrow transplantation in an 8-year-old boy with acute megakaryoblastic leukemia characterized by intense fibrosis together with 20% blast cells in the bone marrow, who was transplanted without preceding chemotherapy for remission induction. Conditioning comprised cytosine arabinoside, cyclophosphamide and total body irradiation. The donor was his HLA-identical sister. The patient is well with minor chronic graft-versus-host disease and normal hematologic values 670 days post-transplant.