Essential Thrombocythemia and Leukemic Transformation

Acute leukemia and myelodysplasia in patients with a Philadelphia chromosome negative chronic myeloproliferative disorder treated with hydroxyurea alone or with hydroxyurea after busulphan

“…In patients with ET, the risk of transformation to AL has been reported on average 5% after being treated with HU. In comparison several studies have shown that the spontaneous transformation of ET to AL is indeed very low, with values of 0.5-1.0% being reported [5,33,40]. Concerning patients with PV, the risk of spontaneous transformation to AL is between 1% and 4% [2,20,32].…”

Acute myeloid leukemia with 17p abnormality in untreated essential thrombocythemia

“…Most of them are related to patients who received cytoreductive treatment during the chronic phase. 5 In contrast, few cases of acute leukemia after untreated ET have been reported and most of them without cytogenetic alterations. 6 The present patient developed AML 10 years after the diagnosis of ET and she had never been treated.…”

Essential Thrombocythemia Terminating in Acute Leukemia with Minimal Myeloid Differentiation -A Brief Review of Recent Literature

“…The incidence of progression to blast crisis is reported to be about 3-5% among patients with ET [4][5][6]. Radioactive phosphorus (32P), and cytoreduc tive agents such as busulfan and hydroxyurea, which have been used in the treatment of ET, are thought to play a causative role in the pathogenesis of leukemic transforma tion [7]. Therefore, the occurrence of blastic crisis may be rarer in untreated patients with ET, as indicated by Fenaux et al [8].…”

“…Therefore, these cases should be considered as a special form of CML with a marked protagonism of the mcgakaryocytic cell line. Besides Ph', the numerical and structural abnormalities of chromosome 21, such as a dele tion of the long arm of chromosome 21 (21 q~), are reported to be a marker for the development of acute transforma tion in ET [16], Second, cytotoxic agents and 32P possess mutagenic potentials, and may be a cause of acute leuke mia in transformed ET [7]. Although there are 5 reported patients without treatment other than our present case during the chronic phase of their disease [9,10,21,22], 4 of them were actually given either myelosupprcssive drugs or radioactive agents for a short time as our patient (table 2).…”