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;121:260-269

©2013 by American Society of Hematology

319-351-0109

Schematic representation of the multistep molecular pathogenesis of RARS-T supporting its nature of true MDS/MPN (combination of SF3B1 and JAK2 or MPL mutations).

Mario Cazzola et al. Hematology 2011;2011:264-272

©2011 by American Society of Hematology