A Case of Ambiguous Lineage Acute Leukemia Posing Diagnostic Challenge

Abstract Introduction/Objective N/A. Methods/Case Report Acute leukemias with ambiguous lineage encompass those that show no clear evidence of differentiation along a single and account for less than 4% all cases acute often poses diagnostic dilemma. We present challenging case an leukemia in previously healthy 27-year-old male, who presented to the ED fever, dyspnea on exertion, nausea vomiting. A complete blood count (CBC) showed white cell 323 × 109/L, Hemoglobin 3.3 g/dl, Platelet 44 109/L differential Neutrophil: 11, Lymphocyte: 31, Monocyte: 02, Band Neutrophil:1, Myelocyte :1, Blast: 54. Bone marrow aspirate smears revealed heterogenous population small large sized blasts comprising 83% cellularity. They expressed scant moderate basophilic cytoplasm, high N/C ratio, round irregular nuclear contour, finely granular chromatin some nucleoli. Other lineages were markedly suppressed. Flow cytometric analysis abnormal blast (~80% total) expressing CD34, HLA-DR, Tdt (subset), CD71 (dim) CD38. In addition, myeloid associated antigens CD13, MPO (smaller subset), as well B-cell CD19 (dim), cytoplasmic CD22 CD79a. also T-cell antigens, CD2, CD3 CD5 (subset) CD7 but negative CD3. This unusual pattern expression posed challenge what type mixed phenotype it should be variable expressions from three myeloid, B- T-cell. Further work-up showed, scattered are positive by cytochemical (on smear) immunohistochemical stain core). The latter negativity Based these findings, this (MPAL) was best categorized MPAL (B/myeloid) over so called “Triphenotypic (B/T/myeloid) leukemia”. considered B markers more defining compared subset T marker exemplifies importance multimodal comprehensive leukemia, especially setting multi- posing challenge. Results (if Case Study enter NA) Conclusion