DE-NOVO MYELODYSPLASTIC SYNDROME (MDS) WITH DELETION OF THE LONG ARM OF CHROMOSOME-20 - A SUBTYPE OF MDS WITH DISTINCT HEMATOLOGICAL AND PROGNOSTIC FEATURES

We report on 8 cases of de novo myelodysplastic syndromes (MDS) with d eletion of the long arm of chromosome 20 (del 20q), who represented ab out 2% (8/392) of our cases of de novo MDS with cytogenetic analysis s een during a period of 9 yr. Median age was 69 yr, and there were 7 ma les and 1 female. Anemia was absent or very mild (fib > 11 g/dl) in 5 patients. Only 1 patient had neutrophils < 0.5 x 10(9)/l, and none had platelets < 50 x 10(9)/l. Four patients had refractory anemia (RA), 2 had refractory anemia with ringed sideroblasts (RARS), and 2 had refr actory anemia with excess of blasts (RAEB). Del 20q was isolated in 5 patients, and associated with other chromosomal rearrangement(s) in 3 patients. Only 1 patient progressed to ANLL and 2 showed an increase i n bone marrow blasts during evolution. The 5 other patients had stable disease after 18-77 months. By comparison with de novo MDS patients w ith other cytogenetic findings, patients with del 20q had a tendency t owards lower incidence of anemia and excess of marrow blasts, lower in cidence of progression to AML and more prolonged survival, although di fferences were not significant. Only patients with isolated del 5q had a more prolonged survival than patients with del 20q.