Trisomy 8 in essential thrombocythemia in leukemic transformation

Leukemic transformation in essential thrombocythemia

Essential thrombocythemia patients develop acute myeloid leukemia (AML) at a rate of 1-4% during a median follow-up of 7-10 years. The risk increases with advanced age, anemia, platelet count ≥ 1000 × 10(9)/l, the presence of ≥ 2 somatic mutations and after the first decade of diagnosis. The use of alkylating agents and (32)radiophosphorus, particularly in higher doses, but not hydroxyurea and anagrelide, increases the risk. AML in essential thrombocythemia patients is frequently associated with unfavorable cytogenetics and poor prognosis. In young and fit patients, AML-type induction chemotherapy followed by allogeneic stem cell transplantation may offer the best chance of long-term disease control. In select elderly patients with poor performance status, hypomethylating agent such as azacytidine may prolong survival.

De novo appearance of der(1;7)(q10;p10) is associated with leukemic transformation and unfavorable prognosis in essential thrombocythemia

Leukemic transformation or myelofibrosis is a major concern in managing patients with chronic myeloproliferative disorders, including essential thrombocythemia (ET). We analyze the relationship between cytogenetic changes and the transformation in 89 patients with ET; 8 patients experienced transformation, including 2 patients with acute leukemia following myelofibrosis, 3 with acute leukemia, and 3 with myelofibrosis. Among the eight patients showing transformation, two patients developing myelofibrosis derived from a group with normal cytogenetics, but the remaining six were categorized as showing de novo appearance of cytogenetic changes. Two leukemia patients had de novo cytogenetic changes at the time of leukemia diagnosis, whereas two patients with acute leukemia following myelofibrosis showed der(1;7) during their myelofibrosis period. Moreover, patients with der(1;7) did not receive any cytotoxic agents before the appearance of der(1;7), indicating that detection of der(1;7) may have predictive value for not only leukemic transformation but also unfavorable prognosis.

A novel t(2;17) in transformation of essential thrombocythemia to acute myelocytic leukemia

A transformation of essential thrombocythemia to acute myelocytic leukemia (AML), myelodysplastic syndrome, or agnogenic myelocytic metaplasia is a relatively rare event. It occurs in 1%-4.5% of all patients with either treated or untreated essential thrombocythemia. Cytogenetic changes in the transformation to AML are common. We report the case of a patient treated for essential thrombocythemia with hydroxyurea for 49 months. He developed AML with a t(2;17), which to our knowledge has not been described in the literature.

Spontaneous evolution of essential thrombocythaemia into acute megakaryoblastic leukaemia with trisomy 8, trisomy 21 and cutaneous involvement

Spontaneous transformation of essential thrombocythaemia (ET) into acute leukaemia is rare. We describe a case of ET that spontaneously transformed after 19 yrs uneventful follow-up into acute megakaryoblastic leukaemia. Cytogenetic analysis of bone marrow nucleated cells showed trisomy 8 and trisomy 21 at time of leukaemic transformation supporting the hypothesis that chromosomal abnormalities are part of the mechanism that drives the leukaemic progression independently of drug cytotoxicity. In addition, the very rare and intriguing finding of M7 FAB subtype evolution of ET was complicated by cutaneous involvement in the leukaemic process.

Acute myeloid leukaemia arising from a patient with untreated essential thrombocythaemia

Acute myeloid leukaemia (AML) is an uncommon complication of patients with essential thrombocythaemia (ET). We report a patient with ET which progressed into AML and who had only received a few days of therapy with hydroxyurea (HU) when diagnosed with ET. This is extremely rare, as in large series no patients who were left untreated for their ET developed this complication. This case supports the theory that AML transformation can be part of the natural history of ET in some cases.

Leukemic transformation with trisomy 8 in essential thrombocythemia: a report of four cases

Karyotype analysis of bone marrow samples was performed in 20 cases of essential thrombocythemia (ET) at the time of diagnosis. Three patients had karyotype abnormalities at the time of diagnosis; trisomy 8, deletion of Y, and del(9)(q?) in each. The patient who had trisomy 8 at the time of diagnosis underwent myeloid blastic transformation in 35 months. Three patients whose karyotypes were normal at the time of diagnosis developed a chromosome abnormality with trisomy 8 when they developed myeloid blastic transformation 38, 79 and 86 months after initial diagnosis of ET. Two patients with blastic transformation had been treated with busulfan, one with hydroxyurea and one with methyl-6-[3-(2-chloroethyl)-3-nitorosoureidol]-6-deoxy-alpha-D-glucopyranoside (MCNU). It is suggested that progression of the disease may have increased the incidence of trisomy 8 and the development of leukemic transformation.

No increased frequency of trisomies 8 and 9 by fluorescence in situ hybridization in untreated patients with essential thrombocythemia

Essential thrombocythemia (ET) is one of the diseases included among the myeloproliferative disorders in which trisomies for chromosomes 8 and 9 commonly occur. In ET, only a few patients are known to show clonal abnormalities. With fluorescence in situ hybridization (FISH), interphase cells can be evaluated and clones can be detected even though not revealed by conventional cytogenetic methods. By using FISH for enumeration of chromosomes 8 and 9 in bone marrow cells, we studied 22 patients with ET; 20 of them were investigated at the time of diagnosis when they were still untreated with myelosuppressive agents. Only two patients had trisomy 8; one of them was also found to have +8 with conventional cytogenetics. None of the patients had trisomy 9; two patients had borderline values in comparison to a control group. Thus, in ET, no increased frequency of patients with trisomy for 8 or 9 at the time of diagnosis could be detected with FISH.