De novo acute B-cell leukemia with translocation t(14;18): an entity with a poor prognosis.

Three cases of de novo acute B-cell lymphoblastic leukemia are presented, all with an unusual phenotype, involvement of translocation t(14;18) and additional chromosomal abnormalities, including translocation t(8;14) and deletion of chromosome 9. In contrast to normal FAB-L2 or FAB-L3 acute lymphoblastic leukemia (ALL), these leukemias did not express cytoplasmatic and membranous immunoglobulin. The combination of translocation t(14;18) and additional chromosomal events on the other chromosome 14 account for the lack of immunoglobulin expression. In one case a low grade follicular lymphoma was found next to a high grade Burkitt type ALL. The translocation t(14;18) takes place as a mistake in the VDJH joining in pre-B cells in the bone marrow. It is proposed that some cases of de novo ALL may arise as a blast crisis induced by genetic events, secondary to the primary t(14;18) translocation. This type of ALL seems to have a poor prognosis.