title: Infant acute bilineal leukemia.
abstract: Most cases of acute leukemia can be assigned to the myeloid, B or T lineage. There are rare cases of acute leukemia, which cannot be clearly classified, because either blasts express antigens of more than one lineage (acute biphenotypic leukemias) or distinct blast populations of two lineages co-exist (acute bilineal leukemias, aBLL). We present a 10-month-old infant with de novo aBLL, characterized by blasts of monocytic and B-cell precursor lineages. All leukemic cells harbored identical complex MLL gene rearrangement. Despite poor initial response, both to acute lymphoblastic leukemia (ALL) induction treatment and acute myeloid leukemia induction blocks, the child reached complete clinical remission with minimal residual disease negative status and was transplanted. Unfortunately, 16 months from HSCT the patient experienced BM relapse with all blasts characterized by pro-B-ALL immunophenotype. This case report illustrates that aBLL is a very aggressive type of acute leukemia that should be individually treated and monitored, particularly in children less than 1 year of age.
authors.affiliation: Department of Pediatric Hematology, Oncology and Haematopoietic Stem Cell Transplantation, University of Medical Sciences, Szpitalna 27/33, 60-572 Poznań, Poland. kderwich@poczta.onet.pl
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Derwich
authors.forename: Lukasz
authors.initials: L
authors.lastname: Sedek
authors.forename: Claus
authors.initials: C
authors.lastname: Meyer
authors.forename: Anna
authors.initials: A
authors.lastname: Pieczonka
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Dawidowska
authors.forename: Anna
authors.initials: A
authors.lastname: Gaworczyk
authors.forename: Jacek
authors.initials: J
authors.lastname: Wachowiak
authors.forename: Benigna
authors.initials: B
authors.lastname: Konatkowska
authors.forename: Michał
authors.initials: M
authors.lastname: Witt
authors.forename: Rolf
authors.initials: R
authors.lastname: Marschalek
authors.forename: Tomasz
authors.initials: T
authors.lastname: Szczepański
mesh_terms: D001402:B-Lymphocytes / Q000187:drug effects / Q000473:pathology*; D019070:Cell Lineage; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007223:Infant; D015456:Leukemia, Biphenotypic, Acute / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D008297:Male; D018365:Neoplasm, Residual / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D012074:Remission Induction; D016896:Treatment Outcome