A complicated but nonrandom karyotype in preleukemia.

A patient with preleukemia who possessed a complicated hypodiploid karyotype in 100% of bone marrow cells is described. The clinical, hematologic, and cytogenetic features showed a marked similarity to a patient with preleukemia described by Watt et al. [1]. Both patients terminated their disease in acute nonlymphocytic leukemia. Another patient with similar cytogenetic features, but who presented in the acute leukemic phase of polycythemia rubra vera, also is described. All three patients possessed a translocation involving chromosome #11 at band p15. This, together with many numerical and structural abnormalities, particularly those involving chromosomes #5, #7, and #17, may prove useful in defining a variety of preleukemia with a poor prognosis.