Diagnosis of secondary myelodysplastic syndromes (MDS) following autologous transplantation should not be based only on morphological criteria used for diagnosis of de novo MDS

Secondary myelodysplastic syndromes (MDS) are increasingly being reported after autologous transplantation. Transient dysplastic changes have also been observed after this type of treatment. However, to the best of our knowledge no systematic morphological analysis has been perfomed to determine the influence of stem cell transplantation on bane marrow morphology. In 53 patients undergoing autologous transplantation, we evaluated the bone marrow, before and 6 and 12 months after the transplant, in order to analyze the appearance of dyshemopoietic changes, assessed according to a pre-established score. We also studied 25 bone marrow samples obtained at the time of diagnosis, prior to treatment, but we did not find morphological atypia. Six months after transplant, cellularity and thrombopoiesis had decreased in 38% and 49% of patients respectively, although 1 year after the process they were normal in most cases. Myelodysplasia was already present in bone marrow before transplantation and continued to be in evidence for a long time afterwards. This suggests that chemotherapy and radiotherapy used prior to transplantation are responsible for dysplastic changes. The myeloid line was the most affected with 100% of patients showing dysgranulopoiesis 1 year after autografting. Cytopenias were observed in 51% and 44% of patients 6 and 12 months after transplantation. Moreover, concomitant presence of cytopenia and myelodysplasia was observed in 37.7% of patients at 6 months after transplantation and 25% at 12 months, and therefore they could be diagnosed with MDS. These data contrast with the incidence of secondary MDS reported in earlier publications. According to these findings, the value of the French-American-British Go-operative Group criteria for the diagnosis of MDS following autologous transplantation is questionable. Moreover, since dyshemopoietic features are almost always present after autologous transplant, morphological criteria are not useful for early recognition of patients with secondary MDS after transplantation.