DE-NOVO ACUTE MYELOID-LEUKEMIA WITH TRILINEAGE MYELODYSPLASIA (AML TMDS) AND MYELODYSPLASTIC REMISSION MARROW (AML/MRM)/

Trilineage myelodysplasia (TMDS) in de novo acute myeloid leukemia (AM L) at initial diagnosis and during remission has not been well recogni zed yet. In this review we describe the characteristics of de novo AML with TMDS (AML/TMDS) and with myelodysplastic remission marrow (AML/M RM) in view of the in vivo and in vitro disease progression. AML/TMDS was found in ten (10.4%) of 96 patients with de novo AML at initial di agnosis and AML/MRM were also observed in three (5.0%) out of 60 cases in remission after chemotherapy in our hospital between 1984 and 1992 . Abnormal karyotypes were seen in six of nine AML/TMDS patients and a ll of the three AML/MRM. Karyotypic changes occurred in two of AML/TMD S and two of AML/MRM during their clinical course. Using the long term bone marrow culture (LTBMC) system that allowed abnormal clones to su rvive preferentially to the clone of normal karyotype, latent clones w ere detected in three patients with AML/TMDS and three of AML/MRM as i n the cases of myelodysplastic syndrome (MDS) and AML transformed from MDS (MDS/AML) but not in the typical AML without myelodysplastic chan ges. Four of these cases exhibited the same karyotypes as seen during the clinical course. Primary abnormal karyotypes prior to clonal evolu tion were also observed in two of the AML/MRM. Taken together, both AM L/TMDS and AML/MRM are similar to MDS/AML with respect to their myelod ysplastic background and potential for disease progression and may hav e progressed to AML from the preceding disease status more rapidly tha n MDS/AML.