[1377] Acute Megakaryoblastic Leukemia in Adults: A Clinico-Pathologic Reappraisal of 50 Cases Using WHO Criteria

Jose M Gonzalez-Berjon, Gary Lu, Srdan Verstovsek, Sherry A Pierce, Carlos E Bueso Ramos, Tariq Muzzafar. Universitiy of Texas MD Anderson Cancer Center, Houston, TX

Background: Acute megakaryoblastic leukemia (AMKL) in adults is a rare disease, and per WHO criteria, diagnosis requires ≥ 20% blasts of which ≥ 50% are of megakaryocytic lineage. The relationship of AMKL to myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS) and to AML with myelodysplasia-related changes is not well characterized. The aim of this study is to better characterize this relationship.
Design: We identified 53 cases diagnosed with AMKL in our institutional files from 01/1994 to 08/2012. We collected demographic and clinical data, including history of hematologic disease, prior chemo/radiation therapy, hematologic parameters at presentation, cytogenetic findings and survival data.
Results: Of the 53 cases, 3 had inv(3)(q21;q26.2) or t(3;3)(q21;q26.2) and per WHO criteria, these were excluded from further analysis. The remaining 50 cases were analyzed. Median age was 58 years, and male/female ratio was 2.8. 19(38%) cases were de novo, 8(16%) cases evolved from MDS, 10 (20%) had history of prior chemotherapy and/or radiation, 11(22%) evolved from MPN, including 5(10%) from primary myelofibrosis, 2(4%) from essential thrombocythemia, 2(4%) from polycythemia vera and 2(4%) myeloproliferative neoplasm unclassifiable. Of the 43(86%) cases for which karyotypic results were available, 8(19%) had diploid karyotype, 35(81%) had abnormal karyotype with 21(49%) being complex (> 3 chromosomal abnormalities). Overall, 27(61%) cases met cytogenetic criteria for AML with myelodysplasia-related changes. Median survival was 26 weeks, with complex karyotype predicting adverse prognosis (p < 0.01). History of chemo and/or radiation therapy, pre-existing MDS or MPN, blast percentage in peripheral blood did not reach statistical significance in survival analysis.
Conclusions: AMKL meets cytogenetic criteria for AML with myelodysplasia-related changes in majority of cases with 42% having complex karyotype. It can present de novo, or transform from MDS (including therapy related) and MPN. Interestingly, in this series, 22% cases evolved from pre-existing MPN, a finding not emphasized previously. Survival is poor with complex karyotype predicting an adverse prognosis.
Category: Hematopathology

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 231, Wednesday Morning


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