[Acute nonlymphocytic leukemias with 21 trisomy as a sole anomaly]

Two cases of childhood acute nonlymphocytic leukemia (ANLL) with 21 trisomy as a sole cytogenetic change are reported. The first case was a 4-year-old boy with FAB-M5a. 47, XY, +21 was found in 7 of 12 metaphases at diagnosis and in all 15 metaphases examined at relapse 4 years and 3 months later. The second case was a 14-year-old boy with FAB-M1, all 20 cells examined showed 21 trisomy at diagnosis. His peripheral blood in remission revealed normal male karyotype. Although 21 trisomy is relatively common in ANLL of children, 21 trisomy as a sole anomaly is extremely rare, and to our knowledge, only 2 cases (19 included adult cases) have previously been reported.