How are refractory anemia (RA) and refractory anemia with ringed sideroblasts (RARS) characterized in the French-American-British (FAB) classifications of myelodysplastic syndrome (MDS)?

Updated: Jul 24, 2018
  • Author: Emmanuel C Besa, MD; Chief Editor: Koyamangalath Krishnan, MD, FRCP, FACP  more...
  • Print
Answer

RA and RARS are characterized by 5% or less myeloblasts in bone marrow. RARS is defined morphologically as having 15% erythroid cells with abnormal ringed sideroblasts (see the image below), reflecting an abnormal accumulation of iron in the mitochondria. Both RA and RARS have a prolonged clinical course and a low prevalence of progression to acute leukemia. In a review of United Kingdom population-based data, with followup of 2 to 11 years, progression to acute leukemia occurred in 5% of RARS cases, compared with 25% of RAEB cases. [13]

Bone marrow film (1000× magnification) demonstrati Bone marrow film (1000× magnification) demonstrating ring sideroblasts in Prussian blue staining in a refractory anemia with excess of blasts in transformation. Courtesy of U. Woermann, MD, Division of Instructional Media, Institute for Medical Education, University of Bern, Switzerland.

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!