Acute transformation of essential thrombocythaemia: report of two cases.

Primary (Essential) Thrombocythemia versus Initial (Hyperplastic) Stages of Agnogenic Myeloid Metaplasia with Thrombocytosis – A Critical Evaluation of Clinical and Histomorphological Data

“…Relevant complications included hemorrhage and thrombosis [2][3][4][5][6]17] mostly in pa tients who received myelosuppressive therapy [2][3][4]6]. Further a number of cases have been described to de velop acute leukemia as terminal event following a prolonged course of disease [4, 7-10, 28, 29], Referral to initial and sequential histopathological features of the bone marrow in these anecdotal reports was mostly limited to the statement of a prominent megakaryocytic hyperplasia at onset and an overall blast population at end-stage disease [8][9][10], In the view of our results derived from a longitudinal study on 26 PTH-patients with an observation period of 1.5-10.5 years, blastic transformation seemed to be an ex tremely rare event. This complication certainly re quires the unequivocal exclusion of any other subtype of CMPD, i.e.…”

“…ings [1][2][3][4], therapeutic modalities [5,6] and complica tions, particularly blastic transformation which may be rarely encountered in PTH [7][8][9][10]. Generally, the diagnostic approach for PTH is done by a stepwise procedure in order to exclude a reactive thrombocyto sis as well as other subtypes of chronic myeloprolifer ative diseases (CMPD) like polycythemia vera rubra (P. vera), chronic granulocytic leukemia (CGL) and agnogenic myeloid metaplasia (AMM) with concom itant thrombocythemia [1][2][3].…”

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

“…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). Finally, bone marrow cells from patients with ET arc known to form few granulocyte-macrophage colony-form ing units (CFU-GM) or granulocyte colony-forming units (CFU-G) in culture.…”

“…Usually, the blasts are myeloid, although there are a few reports of lymphoid crisis in ET [9][10][11]. As Total 50 BU = Busulfan; HU = hydroxyurea; MPL = melphalan; 32P = phorus.…”

Leukaemic Transformation in a Case of Thrombocythaemia

“…The leukaemic blasts are nearly always myeloid in nature, although rare cases of acute lymphoblastic transformation have also been described [5, 6, 7]. In the series of cases studied by Higuchi et al [8], all 5 patients with ET in transformation were found to have megakaryoblastic features and 3 were diagnosed as having acute myeloid leukaemia (AML) subtype M7.…”