[Monoblastic (M5a) form of relapse in acute myeloblastic (M2) leukemia with t(8;21)]

An exceptional case of acute myeloblastic leukemia (M2) with t(8;21) relapsed as an acute monoblastic leukemia (M5). At that time only a minority of metaphases exhibited a t(8;21) and/or abnormality of chromosome No 11 long arm whereas various other chromosomal changes were present. The existence of a relapse of M2 with t(8;21) as M5 is discussed in relation to the commitment of the cells which became leukemic, and to the possibility of a second leukemia.