An exacerbated proliferation of B-cell progenitors in bone marrow can evolve to a Precursor B-cell Acute Lymphoblastic Leukemia (B-ALL). Molecular and chromosomal abnormalities affect differentiation and proliferation of lymphoid precursors. Chromosomal alterations (hypodiploidy and hyperdiploidy), rearrangements involving KMT2A gene and the translocations BCR-ABL (Ph+), TCF3-PBX1 and ETV6-RUNX1 can be used as biomarkers to predict prognostic. The association of hyperdiploidy with chromosomal translocations is observed in 1%‒4% of hyperdiploidy patients in B-ALL. The aim of this study was to describe a rare case of B-ALL in an adolescent with BCR-ABL and hyperdiploidy.

Immunophenotyping was used to characterize the leukemia type. Molecular tests were performed to investigate the presence of recurrent chromosomal translocations in B-ALL. G-banding and Fluorescence in situ hybridization (FISH) were carried out to characterize the karyotype.

A 16-year-old girl was admitted in Hospital Sarina Rolim, São Paulo in February 2019 after experiencing 3 months of recurrent limb pain along with loss of weight, skin pallor and muscle weakness. The peripheral blood count showed 8.800 white blood cells/mm3, platelets count 90.000, hemoglobin 10 g/dL and hematocrit 30%. The immunophenotyping showed: CD19++/+++, CD20−/+/++, CD10+/++/+++, CD66C+/++/+++, CD123−/+/++, CD9+/++/+++, CD127−/+, CD44+++. The RT-PCR was negative for TCF3-PBX1, ETV6-RUNX rearrangements. It was detected the presence of Ph+ (P190). The results were consistent with B-ALL. The karyotype was: 58≍61,XX,+2,+4,+6,+8,t(9;22)(q34;q22),+10,+11,+12,+13,+19,+20,+21,+22,+22,+der(22)[cp16]/46,XX[1]. The patient was treated according to ALL BFM 2009 protocol associated with imatinib 400 mg/day. During the follow-up of minimal residual disease (D33), the patient presented hematological and infectious toxicity stage IV, requiring hospitalization due to febrile neutropenia and sepsis. Also, exhibited aseptic necrosis of the femoral head and underwent orthopedic surgery. The treatment has been completed in February 2021. In July 2022, the patient had no evidence of disease recidive but she acquired modest motor sequelae due to the orthopedic surgery.

Hyperdiploidy occurs in 30% of pediatric B-ALL. The most frequent chromosome gains are X, 4, 6, 10, 14, 17, 18 and 21. However, BCR-ABL translocation comprises 2%‒5% of childhood ALL. There are only a few case reports of patients presenting BCR-ABL associated to hyperdiploidy. The outcome of patients can change according to these variations in genetic factors. Although BCR-ABL is associated with poor prognosis, the outcome has improved with implementation of tyrosine kinase inhibitors in Ph+ patients'therapy.

We described an unusual case of pediatric B-ALL with hyperdiploid and Ph+ karyotype. This study and the literature review demonstrate the importance of cytogenetic and molecular tests during the diagnosis aiding to choose the treatment and improving the survival for ALL pediatric patients.