RATIONALE: Drugs used in chemotherapy, such as decitabine, work in different ways to stop the growth of myelodysplastic cells, either by killing the cells or by stopping them from dividing. Tretinoin and decitabine may help myelodysplastic cells become more like normal cells, and to grow and spread more slowly. Giving decitabine together with tretinoin may be an effective treatment for myelodysplastic syndromes.