Early Pre-B Lymphoblastic Transformation in A Patient with Refractory Anemia

A 77 year-old male with refractory anemia receiving only supportive therapy presented with an acute transformation six years following diagnosis. The lineage of the blast cells could not be ascertained by morphological and cytochemical studies. Nevertheless, immunophenotypical studies, including monoclonal antibodies against myeloid, monocytic, erythroid, megakaryo-cytic and T and B lymphoid antigens, and analysis of immunoglobulin and T-cell receptors genes demonstrated the early pre-B nature of the blasts. Lymphoblastic transformation is extremely rare in myelodysplastic syndromes (MDS). The case presented here and other similar cases previously reported are consistent with the concept that MDS are clonal disorders arising from a pluripotent stem cell.