Clonal evolution of monosomy 7 in acquired severe aplastic anemia: Two cases treated with allogeneic hematopoietic stem cell transplantation.

Aplastic anemia (AA) may evolve into clonal diseases like myelodysplastic syndrome (MDS) and acute myeloblastic leuke¬mia (AML). Monosomy 7 is a poor prognostic chromosomal abnormality commonly associated with therapy related MDS and secondary AML. It has also been associated with leukomogenic transformation in AA. We present here two adult ma¬le patients with acquired severe AA. Both patients had received immunosuppressive therapy (IST) as first line treatment and had monosomy 7 positive clone at transformation to MDS with refractory anemia and excess of blast (RAEB-II) and AML, respectively. Both patients have undergone allogeneic hematopoietic stem cell (HSC) transplantation from their HLA identical donors (unrelated and sibling).