Diagnosis and classification of myelodysplastic syndrome: International Working Group on Morphology of myelodysplastic syndrome (IWGM-MDS) consensus proposals for the definition and enumeration of myeloblasts and ring sideroblasts.
The classification of myelodysplastic syndromes is based on the morphological criteria proposed by the French-American-British (FAB) and World Health Organization (WHO) groups. Accurate enumeration of blast cells, although essential for diagnosis of myelodysplastic syndrome and for assignment to prognostic groups, is often difficult, due to imprecise criteria for the morphological definition of blasts and promyelocytes. An International Working Group on Morphology of Myelodysplastic Syndrome (IWGM-MDS) of hematopathologists and hematologists expert in the field of myelodysplastic syndrome reviewed the morphological features of bone marrows from all subtypes of myelodysplastic syndrome and agreed on a set of recommendations, including recommendations for the definition and enumeration of blast cells and ring sideroblasts. It is recommended that (1) agranular or granular blast cells be defined (replacing the previous type I, II and III blasts), (2) dysplastic promyelocytes be distinguished from cytologically normal promyelocytes and from granular blast cells, (3) sufficient cells be counted to give a precise blast percentage, particularly at thresholds that are important for diagnosis or prognosis and (4) ring sideroblasts be defined as erythroblasts in which there are a minimum of 5 siderotic granules covering at least a third of the nuclear circumference. Clear definitions and a differential count of a sufficient number of cells is likely to improve precision in the diagnosis and classification of myelodysplastic syndrome. Recommendations should be applied in the context of the WHO classification.
Department of Haematology, King's College Hospital, Denmark Hill, London, SE5 9RS United Kingdom. ghulam.mufti@kcl.ac.uk
Ghulam J
GJ
Mufti
John M
JM
Bennett
Jean
J
Goasguen
Barbara J
BJ
Bain
Irith
I
Baumann
Richard
R
Brunning
Mario
M
Cazzola
Pierre
P
Fenaux
Ulrich
U
Germing
Eva
E
Hellström-Lindberg
Itsuro
I
Jinnai
Atsushi
A
Manabe
Akira
A
Matsuda
Charlotte M
CM
Niemeyer
Guillermo
G
Sanz
Masao
M
Tomonaga
Teresa
T
Vallespi
Ayami
A
Yoshimi
D000756:Anemia, Sideroblastic / Q000473:pathology; D003657:Decision Making; D005060:Europe; D042381:Granulocyte Precursor Cells / Q000473:pathology*; D006801:Humans; D007391:International Cooperation; D009190:Myelodysplastic Syndromes / Q000145:classification* / Q000175:diagnosis* / Q000473:pathology; D014481:United States; D014944:World Health Organization