<![CDATA[Introduction: Acute lymphoblastic leukemia (ALL) is one of the rare hematologic malignancies that commonly occurs in children and less commonly in adults. The prior cases reported adults with ALL were having varied clinical manifestations, which sometimes confused the physicians. Additionally, elevated white blood cells are not always present in hematologic malignancies like ALL. Moreover, diagnosing ALL in a tropical country like Indonesia is more challenging because many infection cases have similar manifestations to hematologic malignancies like ALL. Therefore, in this study, we reported a case report of ALL in Indonesia in ordered steps. Case Presentation: We reported a 40-year-old Indonesian male with a 2-week fever, general weakness, and bloody stool who was first suspected as infection. The diagnosis became confusing when the physicians found the laboratory result of anemia (hemoglobin of 8,6 g/dL) and thrombocytopenia (42k/uL), but normal white blood cells and negative markers of any infections or autoimmune disease. Peripheral blood examination resulted in normochromic normocytic anemia and leucopenia without any blast cells found, suggesting bone marrow aspiration (BMA). A proportion of 89% lymphoblast was found in BMA, further confirmed with immunophenotyping, which resulted in positive expression of CD19, CD34, CD79a, CD10, and HLA-DR, impressing ALL-B lineage.Conclusions: It is more challenging to diagnose ALL in a tropical country with many mimicking infectious diseases and varied laboratory findings. The physicians and clinical pathologists should be alert when finding nonspecific clinical manifestations and laboratory findings.]]>
