Biphenotypic acute leukemia or acute leukemia of ambiguous lineage in childhood: clinical characteristics and outcome

BACKGROUND: Acute leukemia (AL), not clearly assigned to myeloid, B-lymphoid, or T-lymphoid lineage, is classified as either biphenotypic acute leukemia (BAL) based on the European Group for Immunological Classification of Leukemias (EGIL) or acute leukemia of ambiguous lineage (ALAL) encompassing acute undifferentiated leukemia (AUL) and mixed-phenotype acute leukemia (MPAL) based on the World Health Organization (WHO) criteria. METHODS: Medical records of children newly diagnosed with BAL or ALAL, based on the EGIL or the 2008/2016 WHO criteria, respectively, admitted at Chonnam National University Hospital in 2001–2017 were retrospectively reviewed. RESULTS: Twelve (3.2%) of 377 AL patients satisfied the BAL or ALAL definitions based on the EGIL or the WHO criteria, respectively. Among 12 patients including 11 with BAL and another with undefined case based on the EGIL criteria, 7 (1.9%) had ALAL based on more stringent 2016 WHO criteria (AUL, 2; MPAL, 5). One patient had MPAL with t(9;22)(q34;q11.2), BCR-ABL+, and two had MLL gene abnormality. ALL-directed regimen was associated with better complete remission rate compared with AML-directed regimen (100.0% vs. 16.7%; P=0.015). The 5-year overall survival (OS) and event-free survival (EFS) were 51.1±15.8% and 51.9±15.7%, respectively. AUL was associated with poor OS and EFS compared with MPAL (0.0% vs. 75.0±21.7%; P=0.008). CONCLUSION: Due to the rarity of the cases, future multicenter, prospective studies incorporating large number of cases are urgently warranted to identify the clinical, biologic, and molecular markers for the prediction of prognosis and determine the best tailored therapy for each patient.

Relapse of Biphenotypic Acute Leukemia as a Breast Mass / 한국유방암학회지

In acute leukemia, leukemic infiltration of the breast is extremely rare. We report a case of biphenotypic acute leukemia (BAL) that presented as a breast mass. A 30-year-old woman presented with a 4-month history of a right breast mass with nipple discharge and easy fatigue. She had received chemotherapy and peripheral blood stem cell transplantation for BAL and had been in complete remission for the last 2 years. Core needle biopsy of the breast mass revealed monomorphous infiltrates of blast cells with round nuclei and fine chromatin, consistent with leukemic infiltration. Subsequent bone marrow biopsy showed diffuse infiltration of immature cells. However, bone marrow karyotyping showed 46, XY, suggesting complete engraftment of transplanted donor cells. This is the report of BAL recurring as a breast mass. In the differential diagnosis of a breast mass, extramedullary relapse should be considered when the patient has a history of leukemia.

t(9;22) with 5'ABL1 Deletion and t(6;19) in Biphenotypic Acute Leukemia / 대한혈액학회지

Biphenotypic acute leukemia (BAL) is a rare type of leukemia, comprises 4% of all acute leukemias. It is more common in adults and the clinical features, as related to marrow dysfunction, are similar to those found in other patients with acute leukemia. BAL commonly shows a dimorphic blast population with, one resembling lymphoblasts and the other resembling myeloblasts. The majority of BAL patients express B-lymphoid and myeloid markers. BAL can be diagnosed by morphologic studies and by a comprehensive panel of immunological markers, as well as cytogenetic/molecular studies, such as fluorescence in situ hybridization (FISH) and reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, its prognosis is relatively poor. We present here a 27 year-old female patient who showed lymphoblasts and myeloblasts on her marrow studies and these cells were positive for myeloid and B-lymphoid markers on the immunophenotypic studies. Chromosome analysis revealed 46,XX,t(6;19)(p23;p13.1),t(9;22)(q34;q11.2). A major (b3a2) type of BCR-ABL1 mRNA transcript was detected by RT-PCR, and a 5'ABL1 deletion was identified by FISH.

A case of biphenotypic acute leukemia with expression of the AML1-ETO gene rearrangement / 대한내과학회지

Biphenotypic acute leukemia (BAL) is a subtype of acute leukemia that expresses two different immunophenotypic lineages, most commonly myeloid and either B- or T-lymphoid lineages. This entity has been defined by a scoring system proposed by the European Group for the Immunological Characterization of Leukemias (EGIL). The prognosis of BAL is regarded as being worse than either acute lymphoid or myeloid leukemia that does not show lineage ambiguity. However, a treatment strategy for BAL has not yet been established. We experienced a case of BAL with the t(8;21) translocation, a favorable cytogenetic rearrangement in acute myeloid leukemia (AML). The patient was successfully treated with cytarabine and anthracycline for induction and consolidation. The quantitative value of the AML1-ETO gene decreased after achieving complete hematologic remission. Thus, the AML1-ETO gene rearrangement in BAL may be associated with an acceptable response to the treatment strategy for AML.

Biphenotypic Acute Leukemia with BCR-ABL mRNA Transcript b3a2 Type: A Case Report with Review of the Literature / 대한진단검사의학회지

Biphenotypic acute leukemia (BAL) is a subtype of leukemia of ambiguous lineage in the World Health Organization classification system. About one third of the cases have the Philadelphia chromosome, and some cases are associated with other structural abnormalities involving 11q23. BAL is known to have a poor prognosis in both children and adults. According to the previously reported BAL cases with positive BCR-ABL fusion gene, most of the BCR-ABL mRNA transcript type was e1a2. So, we describe here a 30-year-old adult BAL case with the karyotype 46,XY,t(9;22)(q34;q11.2) resulting in a very rare b3a2 type of BCR-ABL mRNA transcript.