Trisomy 5 as sole anomaly in acute lymphoblastic leukemia.

We present a case of B-cell acute lymphoblastic leukemia (ALL) in whose leukemic cells trisomy 5 (+5) was the only cytogenetic anomaly observed. This is the first report of +5 as the sole cytogenetic abnormality in ALL; two cases (one questionable) of acute nonlymphocytic leukemia with such a change have been reported. The findings are presented in relation to other cases with +5 as part of a more complicated cytogenetic picture in hematologic disorders.