<p>Acute lymphoblastic leukemia (ALL) is a malignant disease characterized by the clonal proliferation of precursor lymphoblasts in the bone marrow. Granular acute lymphoblastic leukemia (G-ALL) is a rare subtype of ALL, primarily associated with B-cell lineage. Traditionally, cytoplasmic granules indicate myeloid leukemia cell differentiation, as primitive lymphoblasts typically lack cytoplasmic granules. Therefore, the immature lymphoblasts in G-ALL may be mistaken for granular myeloid progenitor cells, causing potential diagnostic errors. The involvement of the BCOR gene in acute lymphoblastic leukemia has not been well-documented. This study examines the clinical data of a G-ALL patient, reviews relevant literature, and aims to improve disease recognition among clinicians and laboratory personnel, enhance diagnostic accuracy, and reduce instances of misdiagnosis and mistreatment.</p>