A comprehensive analysis of aberrant immunophenotypes in T-ALL

T cell Acute Lymphoblastic Leukemia (T-ALL) is an aggressive hematologic malignancy characterized by the clonal proliferation of immature T lymphocytes. It accounts for approximately 15% of childhood ALL cases. Aberrant expression of immunophenotype markers is not uncommon in Acute leukemia, especially T-ALL. Aberrrant phenotype in T ALL previously are CD10, CD19,CD79a, CD13, CD33, CD117, CD15 and CD11b. In this case series, we describe clinicopathological profile of 7 T ALL cases with aberrant immunophenotype. All cases diagnosed as T ALL on flow cytometry over a period of 2.5 years were included in this study with emphasis on cases expressing aberrant immunophenotype.Among 29 diagnosed cases T ALL, 8 cases exhibited expression of aberrant markers CD10 (6 cases, paediatric), CD33 (1 case, paediatric),CD117 (1 case, paediatric)co expression of CD10 and CD33 (1 case, paediatric), co expression of CD10, CD79a and CD13 (1 case, adult). The detection of aberrant immunophenotypic markers in T-ALL poses considerable diagnostic challenges. The study underscores the importance of comprehensive diagnostic workup including flowcytometry in managing atypical presentations of T-ALL. It highlights the diagnostic complexity of common & uncommon aberrant immunophenotypes in T-ALL, emphasizing the need for detailed molecular and immunophenotypic profiling to guide treatment planning.In our study, CD10 was found to be the most common aberrant immunophenotype as reported previously. The only adult patient with aberrant immunophenotype had coexpression of 3 CD markers and 1 paediatric case coexpressed 2 CD markers which is rare. None of our cases showed aberrant expression of CD19, CD15 and CD11b.