Introduction: Biphenotypic acute leukaemia is an uncommon type of leukaemia whose blasts co-express myeloid and B-or T-lymphoid antigens.
Case report: We describe two cases of paediatric patients with biphenotypic acute leukaemia. A four-year-old female patient was found to have myeloid and B-lymphoid associated antigens in the same blast cells. Cytogenetic analysis showed a Philadelphia (Ph) positivity t (9;22) (q34;q1l1 with rearrangements of M.bcr-Abl (p210). She was treated with combined acute myeloid leukaemia/acute lymphoblastic leukaemia induction therapy followed by autologous stem cell transplantation. The patient died due to the complications of stem cell transplantation procedure. Another patient was a 20-month-old girl with myeloid and T-lymphoid associated antigens in the blast cells and with normal karyotype. She received acute myeloid leukaemia induction therapy. She has never achieved remission.
Discussion: Immunophenotype is essential to establish the diagnosis of biphenotypic acute leukaemia according to the scoring system adopted by the European Group of Immunological Classification of Leukaemia. There is no agreement about uniformity in treatment for the patients with this type of leukaemia. Biphenotypic acute leukaemia is a high risk leukaemia which requires a more intensive treatment.
Conclusion: Therapy for every patient with biphenotypic acute leukaemia should depend on their immunophenotype and gene rearrangement profiles.