Pediatric Myelodysplastic Syndrome In Japan and China According to 2008 WHO Classification

Abstract 5030

Unlike adult myelodysplastic syndrome (MDS), most of children with MDS have hypocellular bone marrow. Thus, distinguishing MDS from aplastic anemia (AA) can be diagnostically challenging in these patients. To clarify the frequency of pediatric MDS and AA with hypocellular bone marrow in eastern Asia, Japanese and Chinese pediatric hematologists and pathologists conducted a review of 100 patients with cytopenia (50 from Japan, 50 from China). Films stained with both peripheral blood (PB) and bone marrow (BM) along with specimens of BM trephine biopsy were available for all of the patients examined. Patients included 45 males and 55 females, with a median age at diagnosis of 9 years (range: 1 to 19 years). A total of 76 patients had pancytopenia at the time of diagnosis, while 23 had bi-cytopenia and 1 had isolated thrombocytopenia. The medium internal from onset to diagnosis was 319(1–4165) days. Most children present with nonspecific symptoms as a result of cytopenia, including pallor(24%), fatigue(11%), petechiae (27%), bleeding (31%), fever (19%) and infections (10%). Hepatosplenomegaly is uncommon. Before diagnosed, 7% of patients had idiopathic thrombocytopenic purpura (ITP) and 8% of patients had other diseases such as asthma, pneumonia and etc. Cytogenetic analyses performed in 75 patients indicated the karyotype was normal in 45 patients, while 4 had trisomy 8, 1 had monosomy 19, and 2 had trisomy 2. Other abnormalities found included t(X;3)(p11.2;q13), add(6)(p21), and +6. The final diagnoses reached by consensus among the hematologists for the 100 patients included AA in 30 cases, refractory cytopenia of childhood (RCC) in 59 cases, and refractory cytopenia with multi lineage dysplasia (RCMD) in 11 cases. The distribution of the subtypes in the Japanese and Chinese cases were 14:16 for AA, 33:26 for RCC, and 3:8 for RCMD, respectively. In 9 of the patients, the hematologists and pathologists could not agree on the final diagnosis. In 5 of these cases, the hematologists diagnosed the patients as AA, while the pathologists diagnosed RCC. We analyzed the difference between pediatric hematologists and pathologists are the quality of bone marrow and biopsy samples' disparity. Overall, our results suggest that there is no difference in the distribution of the MDS subtypes between Japanese and Chinese children. In order to ensure there is a correct diagnosis of childhood MDS, cooperation between hematologists and pathologists is indispensable.