Treatment of Refractory Anemia with Ring Sideroblasts Associated with Marked Thrombocytosis with Lenalidomide in a Patient Testing Negative for 5q Deletion and JAK2 V617F and MPL W515K/L Mutations.

Refractory anemia with ring sideroblasts associated with marked thrombocytosis (RARS-T) is a hematologic malignancy that often results in transfusion dependency and a hypercoagulable state. This rare disease currently lacks formal guidelines for treatment; however, various case reports have demonstrated efficacy in the use of lenalidomide. This immunomodulatory drug has shown promise in patients with 5q deletions, with reports of achieving transfusion independence and normalization of platelet counts. Herein we present the case of a 68-year-old African American woman with RARS-T who tested negative for 5q deletion and JAK2 V617F and MPL W515K/L mutations. Her treatment with lenalidomide therapy resulted in a five-year durable complete clinical response.