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 a fter autologous transplantation. Transient dysplastic changes have also bee n observed after this type of treatment. However, to the best of our knowle dge no systematic morphological analysis has been perfomed to determine the influence of stem cell transplantation on bane marrow morphology. In 53 pa tients undergoing autologous transplantation, we evaluated the bone marrow, before and 6 and 12 months after the transplant, in order to analyze the a ppearance of dyshemopoietic changes, assessed according to a pre-establishe d score. We also studied 25 bone marrow samples obtained at the time of dia gnosis, prior to treatment, but we did not find morphological atypia. Six m onths after transplant, cellularity and thrombopoiesis had decreased in 38% and 49% of patients respectively, although 1 year after the process they w ere normal in most cases. Myelodysplasia was already present in bone marrow before transplantation and continued to be in evidence for a long time aft erwards. This suggests that chemotherapy and radiotherapy used prior to tra nsplantation are responsible for dysplastic changes. The myeloid line was t he most affected with 100% of patients showing dysgranulopoiesis 1 year aft er autografting. Cytopenias were observed in 51% and 44% of patients 6 and 12 months after transplantation. Moreover, concomitant presence of cytopeni a and myelodysplasia was observed in 37.7% of patients at 6 months after tr ansplantation and 25% at 12 months, and therefore they could be diagnosed w ith MDS. These data contrast with the incidence of secondary MDS reported i n earlier publications. According to these findings, the value of the Frenc h-American-British Go-operative Group criteria for the diagnosis of MDS fol lowing autologous transplantation is questionable. Moreover, since dyshemop oietic features are almost always present after autologous transplant, morp hological criteria are not useful for early recognition of patients with se condary MDS after transplantation.