Patient selection criteria and final diagnosis after a clinicopathologic review process. We selected patients with the following characteristics: (1) a diagnosis of BCR/ABL-negative myeloid neoplasm with the exclusion of polycythemia vera; (2) ringed sideroblasts of 15% or greater, platelet (PLT) count of 450 × 109/L or greater, or both. Overall, 187 patients were identified fulfilling these selection criteria: (1) 89 patients had ringed sideroblasts of 15% or greater and a PLT count less than 450 × 109/L at the time of diagnosis; (2) 24 patients had ringed sideroblasts of 15% or greater and a PLT count of 450 × 109/L or greater (range, 453-1420 × 109/L); (3) 74 patients had a PLT count of 450 × 109/L or greater (range, 458-1308 × 109/L) with less than 15% ringed sideroblasts in the BM. After the clinicopathologic review process of the original cohort of 187 patients, 94 were found to be affected with MDS, 66 with MPN, and 27 with MDS/MPN (19 cases of RARS-T; 5 cases of MDS/MPN, U without ringed sideroblasts; and 3 cases of chronic myelomonocytic leukemia). In 5 patients with MDS, thrombocytosis was associated with an inflammatory condition and regressed later on, so that a diagnosis of reactive thrombocytosis was made.
