Page 194 - Clinical Hematology Atlas

178 SECTION FOUR LEUKOCYTES

yelodysplastic syndromes (MDSs) are acquired clonal hematological disorders charac-
Mterized by normocellular/hypercellular marrow, ineffective hematopoiesis that leads to
progressive cytopenia, and dysplasia in peripheral blood, reflecting maturation defects in
erythrocytes, leukocytes, and/or platelets.
MDSs are heterogeneous and have a multitude of expressions; however, two morpho-
logic findings are common to all types of MDS: the presence of progressive cytopenias in
spite of a cellular bone marrow and dyspoiesis in one or more cell lines. Subtypes of the
2008 World Health Organization classification of MDSs are listed in Box 18-1.

BOX 18-1 World Health Organization
Classification of Myelodysplastic
Syndromes (2008)

Refractory cytopenia with unilineage dysplasia
Refractory anemia with ringed sideroblasts
Refractory cytopenia with multilineage dysplasia
Refractory anemia with excess blasts
Myelodysplastic syndrome with isolated del(5q)
Myelodysplastic syndrome, unclassifiable
Childhood myelodysplastic syndrome
(provisional)
From Swerdlow SH, Campo E, Harris NL, et al, editors: WHO
classification of tumours of haematopoietic and lymphoid
tissues, ed 4, Lyon, France, 2008, IARC Press.

All photomicrographs are 31000 original magnification with Wright-Giemsa staining unless stated
otherwise.