Marked hypodiploidy in a case of acute undifferentiated leukemia

A-29-year-old white man with acute undifferentiated leukemia had bone marrow cells with predominantly 42 chromosomes including several rearrangements. Following a brief induced "complete" remission, during which normal chromosomes were observed, bone marrow cells with 42 chromosomes but a different karyotype than before remission were found. Evaluation of that karyotype indicates not only a reduced chromosome count but also a reduced quantity of chromosome material.