A case of lineage switch from B-cell acute lymphoblastic leukaemia to acute myeloid leukaemia. Role of subclonal/clonal gene mutations

We report the case of a patient with acute lymphoblastic leukaemia (ALL) who displayed a myeloid phenotype at relapse; the molecular IGH marker was conserved in the different phases of the disease. Next‐generation sequencing (NGS) analyses were performed to further characterize this peculiar case. A 40‐year‐old Caucasian female was admitted to our centre in November 2008 with axillary lymphadenopathy. Peripheral blood cell count showed anaemia, thrombocytopenia and a mild leucocytosis; peripheral blood smear morphology revealed the presence of myeloperoxidase‐negative blasts. Bone marrow (BM) aspirate showed 96% blast infiltration and the immunophenotype was diagnostic of a pro‐B ALL (Table ). No fusion genes were detected, while a 46 XX, t(2;16) (p11;p11) karyotype was found in 10/20 metaphases. The cerebrospinal fluid was negative for leukaemic infiltration