APPEARANCE OF LARGE GRANULAR LYMPHOBLASTS AT RELAPSE IN ACUTE LYMPHOBLASTIC-LEUKEMIA

Clonal variations and shifts in the phenotype and karyotype of the bla st cells at relapse in acute lymphoblastic leukemia (ALL) have been re ported. Here we report a striking morphologic alteration in the blast cells, at relapse, in a 15-year-old boy with ALL. In this patient, whi le the lymphoblasts were completely in L1 morphology of French-America n-British classification, large granular lymphoblasts resembling natur al killer cells predominated at relapse. The immunophenotype of these large granular cells, however, was compatible with T-cell ALL. Althoug h the lack of initial karyotype and phenotype data precludes any concl usion about lineage or karyotype switching in our patient, we believe that it is worthwhile to report such a striking morphologic finding in ALL.