Refractory anaemia with ring sideroblasts associated with marked thrombocytosis (RARS-T) and JAK2(V617F) mutation transformed to acute myeloid leukaemia with chromosomal evolution including monosomy 7

About 50% of patients with refractory anaemia with ring sideroblasts and marked thrombocytosis (RARS-T) show a JAK2V617F mutation, and have a relatively favourable prognosis. We report a RARS-T JAK2 positive case transformed to acute myeloid leukaemia with chromosomal evolution including monosomy 7 and persistent JAK2V617F mutation. A 70 year old woman presented with moderate anaemia and elevated platelet count (915 x 109/l), without organomegaly. Sideremia and karyotype were normal. There were no BCR/ABL rearrangements. A JAK2V617F mutation was found. The marrow aspirate showed 20% ring sideroblasts. The biopsy showed a marked erytroid hyperplasia with dyserythropoiesis, and a marked megakaryocytic proliferation with some dysplastic changes. There were 2% CD34 positive blasts. The patient was treated with packed RBC transfusions, erythropoietin and hydroxyurea. Two years later she died of acute myeloid leukaemia with complex karyotype: 44,XX. -7, -16, del(5)(q13q33). JAK2 V617F mutation persisted. RARS-T cases are very rare. They were suggested to represent MPN or MDS cases that have aquired ring sideroblasts, so that the continuing necessity for this category is questioned. Compared to RARS or essential thrombocythaemia, our RARS-T case rapidly evolved to acute myeloid leukaemia, possibly derived from the same neoplastic clone. The the clinical and pathological features of the present case suggest that RARS-T with JAK2 V617F mutation should be regarded as a separate entity.