Summary: | Mixed phenotypic acute leukemia (MPAL), classified under acute leukemia of ambiguous lineage, pose diagnostic dilemma due to multiple lineage-specific antigen expression. World Health Organization has laid down strict criteria for assigning >1 lineage to a single blast population. Most reported cases of biphenotypic acute leukemia belong to myeloid/B-cell lineage or myeloid/T-cell lineage. However, MPAL with B-/T-cell phenotype is very rare. A 5-year-old girl was admitted with fever, petechial rash, pallor, generalized lymphadenopathy, and hepatosplenomegaly. Complete blood counts revealed leukocytosis, anemia, and thrombocytopenia. Bone Marrow Aspiration showed 97% blasts which were negative for myeloperoxidase, and nonspecific esterase. Immunophenotyping showed a single compact population of blasts which expressed CD19, CD79a, CD22, cytoplasmic CD3, and CD7. Thus, flow cytometric immunophenotyping helped to establish a final diagnosis of MPAL: B/T-cell type.
|