Cases with the PICALM-MLLT10 fusion gene can involve a diagnostic dilemma for the following reasons: (1) the fusion gene occurs very rarely, (2) the cases do not have a distinct myeloid or lymphoid morphology and cells often appear immature, (3) cases usually have a mixed T-cell and myeloid phenotype, and (4) cases often have a mixed clinical presentation (e.g., mediastinal mass in a patient with AML).     ///    " Patients with various hematologic malignancies, including acute lymphoblastic leukemia (ALL), acute myeloblastic leukemia (AML), diffuse histiocytic lymphoma, and granulocytic sarcoma, have sometimes been shown to carry the PICALM-MLLT10 fusion gene (alias CALM-AF10) by various cytogenetic methodologies. "    ///    Acute leukemia with PICALM-MLLT10 fusion gene: diagnostic and treatment struggle..     ///    "Routine acute leukemia fluorescence in situ hybridization panels do not include a probe for the PICALM-MLLT10 fusion gene, and therefore diagnosis can be made only when karyotyping is available. "    ///    A 27-year-old woman was diagnosed with AML with the PICALM-MLLT10 fusion gene.     ///    "The case report and literature review here (including discussion of the poor prognosis and of management, including CNS prophylaxis) are intended to raise awareness and to inform about PICALM-MLLT10 in acute leukemia.. "