Thrombocytopenia or thrombocytosis? Nancy Rosenthal, MD

Case history 65 year old female Outside case referred for a second opinion No CBC data was sent with the case

Refractory anemia with ring sideroblasts associated with marked thrombocytosis (RARS-T) New WHO (coming 2016) will likely change this from a provisional to a full entity Classified as an overlap syndrome (MDS/MPN) Must be a de novo diagnosis, not arising from an myelodysplastic syndrome with ring sideroblasts Often has both a JAK2 mutation and SF3B1 mutation

RARS-T MPN –like – Thrombocytosis – Need cytoreduction – Megs are clustered, bulbous, large – JAK2+, rarely CALR/MPL+ MDS- like – Macrocytic anemia – Require transfusions – Ring sideroblasts – Erythroid dyspoiesis – SF3B1+ (80-90%)

Schematic representation of our current understanding of the relationship between the occurrence of a somatic SF3B1 mutation and the formation of ring sideroblasts in patients with RARS. Previous studies found reduced expression of ABCB7 in CD34-positive ce... Cazzola M et al. Blood 2013;121: ©2013 by American Society of Hematology