The French-American-British classification scheme of myelodysplastic syndromes includes a category of refractory cytopenia that includes refractory thrombocytopenia (RTC). Because dysmegakaryopoiesis manifesting as an isolated cytopenia can be difficult to identify morphologically and because it may be accompanied by megakaryocytic hyperplasia, RTC may be confused with idiopathic thrombocytopenic purpura. A review of 1,220 cases of myelodysplastic syndromes at Mayo Clinic Jacksonville and Mayo Clinic Rochester from 1979 to 1990 yielded 9 cases (0.7%) of isolated thrombocytopenia (RTC) associated with clonal chromosome abnormalities. Review of 319 marrow chromosome analyses performed at the cytogenetics laboratory at Mayo Clinic Rochester from 1979 to 1990 for patients with low platelet count yielded two additional cases of RTC (0.6%). Of the 11 RTC cases, 3 previously had been misdiagnosed as idiopathic thrombocytopenic purpura. All patients had oval macrocytes in peripheral blood smears and abnormal megakaryocyte morphology in bone marrow aspirates, lacked antiplatelet antibodies, and did not have splenomegaly on clinical examination. The most common clonal chromosome abnormalities involved chromosomes 3, 5, 8, or 20. Steroid therapy was ineffective. Clinical and laboratory findings can establish the diagnosis of RTC and allow the physician to avoid recommending inappropriate therapy (steroids or splenectomy) for these patients.

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From July 1980 to November 1985, 109 patients with acute myelogenous and lymphoblastic leukemia who had reached a complete remission (CR) following induction treatment were assigned to a study comparing marrow transplantation with chemotherapy as a postremission treatment. Sixty-nine patients did not have a human leukocyte antigen (HLA)-identical donor, and therefore served as chemotherapy controls; 40 patients had HLA-identical donors, and therefore were assigned to the transplant arm. Of these, 23 were transplanted in first remission and 17 were not. Ten of these 17 were subsequently transplanted in relapse. Initially, only patients with poor prognosis determined by a predictive model were entered into the study. Subsequently, patients with moderately poor prognosis were admitted. Comparing the chemotherapy group with the patients transplanted in first CR, significant control of leukemia relapse in transplanted patients was seen in the subgroup with acute myelogenous leukemia (AML) (P less than .1), and acute lymphoblastic leukemia (ALL) (P less than .01), in the poor (P = .01) and intermediate subgroup (P = .01), and in the good-prognostic groups (P = .05). The survival was affected significantly in only the poor and intermediate subgroups. The use of predictive models might help to select patients for whom bone marrow transplantation is appropriate in first remission and those for whom bone marrow transplantation can be left as the initial treatment of relapse. Predictive models could further be helpful in comparing studies performed at different transplant centers.

A high dose combination chemotherapy regimen (CBV) consisting of cyclophosphamide (1.5 gm/m2 day 1 to day 4); BCNU (300 mg/m2 day 1) and etoposide (100 mg/m2 every 12 hours for 6 doses), followed by bone marrow transplant from human leukocyte antigen (HLA) identical sibling donors, was evaluated in 29 patients in whom acute leukemia was in relapse or remission. Engraftment of donor cell type occurred in all but one of 21 patients, in whom marker differences between donor and recipient were established. Two of 11 patients transplanted during relapse of the disease, lived beyond 1 year after bone marrow transplantation. One patient died free of leukemia, 41 months after transplantation of meningitis. Two of seven patients transplanted during the second remission of the disease, are alive and free of leukemia at 42+, and 8+ months. All patients transplanted during the third or fourth remission of the disease have died from either a further relapse, or transplant related causes. The low incidence of organ toxicity with CBV allows for further dose escalation of its drug components.