engleski

Outcome in a small series of biphenotypic acute leukemia (BAL) patients.

Background: Less than 5% of all cases of acute leukemia are classified as biphenotypic acute leukemia (BAL). Being a distinct entity recognized by the WHO classification, BAL is immunophenotypically defined by the European Group for the Immunological Classification of Leukemia (EGIL) scoring system, whereas according to FAB classification BAL may present as one of the ALL or AML subtypes. Since BAL is both a rare form of acute leukemia and shows diverse biological features, there is no consensus on the best treatment approach in these patients. Aim: Our aim was to analyze the laboratory characteristics and the outcome of patients diagnosed with BAL. Patients and methods: Using the EGIL system, we identified 21 cases (4%) of BAL from 535 newly diagnosed acute leukemia patients in the Zagreb Clinical Hospital Center in the period from end 1994-2006. Results: There were 16 male and 5 female patients with median age of 44 years (16- 74). Among them, there were 12 cases of B+myeloid leukemia (55%), 8 cases of T+myeloid (36%), 1 case of B+T lymphoid (5%) and 1 case of trilineage B+T+myeloid leukemia (5%). Morphologic assessment showed myeloid features in 9, lymphoid features in 6 and undifferentiated in 6 patients. Cytogenetic findings revealed normal as well as a wide range of aberrant karyotypes. The patients were treated according to the protocols for AML or ALL or with low-dose chemotherapy - 8, 10 and 3 patients, respectively. In the majority of patients overall survival was poor with a median of 7 months (1- 100) and with a probability of survival at two years of 35%. Conclusion: Despite the progress in the treatment of acute leukemia, the definition and the prognosis of BAL remains poor. Current treatment approach is heterogeneous and still based on cytomorphology. Treatment protocols designed specifically for this type of leukemia should be devised and studied in larger groups of patients.

biphenotypic leukemia; diagnosis; prognosis

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