Introduction: Mixed phenotype acute leukemia (MPAL) is a rare subset of acute leukemia where the blasts exhibit lineage specific antigens of more than one lineage. Flow cytometric immunephenotyping is essential for the diagnosis of MPAL and the accurate diagnosis highly depends on the panel of markers used. The aim of the study is to study the incidence, clinical presentation, haematological parameters, immunophenotypic, molecular features of MPAL and their correlation to the treatment and prognostic significance. 

Materials and Methods:  Cases of Acute Leukemia consisting of both the paediatric and adult age group admitted to the department of Haematology S C B Medical College and Hospital Cuttack, Odisha from September 2015 to November 2016 were analysed.

Results: During the study period, flow cytometric analysis of 680 cases was performed. B lymphoblastic leukemia was the most common subtype of acute leukemia. A diagnosis of MPAL was made in 24 cases, which accounted for 3.5% of all leukemias. 13 cases were diagnosed as B/myeloid, 10 cases as T/myeloid and 1 case as B/T/myeloid.19 of 24 cases received induction chemotherapy and 10 cases achieved complete remission. The overall median survival of all patients in our study was 10 months and the survival at 15 months was 38 %.. The survival of pediatric patients at the end of 15 months was 62% and that of adults was 32%. 

Conclusion: Mixed phenotype acute leukemia is a rare subset of acute leukemia. Flow cytometry is critical in establishing a diagnosis of MPAL. Outcome-related prognostic factors include age, HLA-DR, CD34 negativity. BCR-ABL fusion and MLL rearrangement are associated with poor prognosis. Complete remission is achieved more in cases of ALL directed therapy than AML regimen and more in cases of paediatric patients than in adult cases.

Keywords: B/myeloid, T/myeloid and B/T/myeloid.

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Dharma Niranjan Mishra

Department of Anatomy SCB Medical College, Cuttack, Odisha, India