Myelodysplastic syndrome classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Nawal Muazam M.D.[2]

Overview

The myelodysplastic syndrome may be classified into several subtypes based on the French-American-British (FAB) classification and theWorld Health Organization (WHO) classification methods.

Classification

Myelodysplastic syndrome may be classified according to the French-American-British classification into five groups: Refractory anemia, refractory anemia with ring sideroblasts, refractory anemia with excess blasts, refractory anemia with excess blasts in transformation, and chronic myelomonocytic leukemia.
The table below lists FAB classification for myelodysplastic syndrome:^[1]


Name	Description

Refractory anemia	Less than 5% primitive blood cells (myeloblasts) in the bone marrow and pathological abnormalities primarily seen in red blood cell precursors.
Refractory anemia with ring sideroblasts (RARS)	Less than 5% myeloblasts in the bone marrow, but distinguished by the presence of ringed sideroblasts which may compose greater than 15% of red blood cell precursor in the marrow.
Refractory anemia with excess blasts (RAEB)	5-20% myeloblasts in the marrow
Refractory anemia with excess blasts in transformation (RAEB-T)	21-30% myeloblasts in the marrow (>30% blasts is defined as acute myeloid leukemia)
Chronic myelomonocytic leukemia (CMML)	Less than 20% myeloblasts in the bone marrow and greater than 1*109/L monocytes in peripheral blood

The table below lists World Health Organization classification for myelodysplastic syndrome:^[1]^[2]^[3]


2008	2016
Refractory cytopenia with unilineage dysplasia (RCUD) Refractory anemia (RA) Refractory neutropenia (RN) Refractory thrombocytopenia (RT)	MDS with single lineage dysplasia (MDS-SLD)
Refractory anemia with ring sideroblasts (RARS)	MDS with ring sideroblasts (MDS-RS) MDS-RS-SLD MDS-RS-MLD
Refractory cytopenias with multilineage dysplasia	MDS with multilineage dysplasia (MDS-MLD)
Refractory anemia with excess blasts (RAEB) RAEB-1 RAEB-2	MDS with excess blasts (MDS-EB) MDS-EB-1 MDS-EB-2
MDS with isolated del(5q)	MDS with isolated del(5q)
MDS, unclassifiable (MDS-U)	MDS, unclassifiable (MDS-U)
Refractory cytopenia of childhood (provisional)	Refractory cytopenia of childhood (provisional)

References

↑ ^1.0 ^1.1 Pathologic systems of myelodysplastic syndrome. National Cancer Institute (2015). http://www.cancer.gov/types/myeloproliferative/hp/myelodysplastic-treatment-pdq/#link/_204_toc. Accessed on December 7, 2015
↑ Hong M, He G (September 2017). “The 2016 Revision to the World Health Organization Classification of Myelodysplastic Syndromes”. J Transl Int Med. 5 (3): 139–143. doi:10.1515/jtim-2017-0002. PMC 5655460. PMID 29085786.
↑ Arber, D. A.; Orazi, A.; Hasserjian, R.; Thiele, J.; Borowitz, M. J.; Le Beau, M. M.; Bloomfield, C. D.; Cazzola, M.; Vardiman, J. W. (2016). “The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia”. Blood. 127 (20): 2391–2405. doi:10.1182/blood-2016-03-643544. ISSN 0006-4971.

Overview