title: Congenital B-lymphoblastic leukemia with a cryptic MLL rearrangement and post-treatment evolution to mixed phenotype acute leukemia.
abstract: Congenital leukemia is a rare event with a poor prognosis. We report a case of congenital leukemia with a cryptic rearrangement of MLL demonstrable only with RT-PCR. Interestingly, with treatment, the patient showed lineage plasticity of the leukemia with the development of monocytic lineage blasts after presenting with B-cell lineage blasts. This was heralded by the development of a new clonal cytogenetic abnormality. This case highlights the primitive nature of the leukemic cells in congenital leukemia, and emphasizes that RT-PCR for MLL rearrangements may identify a subset of cases which are otherwise negative by karyotyping, FISH, and chromosomal microarrays.
authors.affiliation: Veteran Administration Greater Los Angeles Healthcare, West Los Angeles Medical Center, 11301 Wilshire Blvd., Los Angeles, CA 90073, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Moschiano
authors.affiliation: Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd., Los Angeles, CA 90027, USA.
authors.forename: Gordana
authors.initials: G
authors.lastname: Raca
authors.affiliation: Children's Center for Cancer and Blood Diseases, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd., Los Angeles, CA 90027, USA.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Fu
authors.affiliation: Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd., Los Angeles, CA 90027, USA.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Pattengale
authors.affiliation: Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd., Los Angeles, CA 90027, USA.
authors.forename: Mathew J
authors.initials: MJ
authors.lastname: Oberley
keywords: Congenital leukemia; Lineage switch; MLL rearrangement; MPAL