Myelodysplastic syndromes/neoplasms: recent classification system based on World Health Organization Classification of Tumors - International Agency for Research on Cancer for Hematopoietic and Lymphoid Tissues

Abstract

The myelodysplastic Syndromes (MDS) are a group of clonal hematopoietic stem cell diseases characterized by cytopenia(s), dysplasia in one or more of the major myeloid cell lines, ineffective hematopoiesis, and increased risk of development of acute myeloid leukemia. The classification and the diagnostic criteria have been redefined by the recent World Health Organization Classification of Tumors - International Agency for Research on Cancer for Hematopoietic and Lymphoid Tissues. The myelodysplastic syndromes are now classified into the following categories - refractory cytopenia with unilineage dysplasia, refractory anemia with ring sideroblasts, refractory cytopenia with multilineage dysplasia, refractory anemia with excess blasts, myelodysplastic syndrome associated with isolated del (5q), myelodysplastic syndrome - unclassifiable, and childhood myelodysplastic syndrome. The clinicopathologic features, morphology, differential diagnosis, immunophenotyping, cytogenetics, prognosis and predictive factors are presented in the light of recent World Health Organization Classification of Tumors - International Agency for Research on Cancer.

Keywords: leukemia; myelodysplastic syndromes.

Figure 1

Refractory cytopenia with unilineage dysplasia (RCUD). Bone marrow aspirate (Wright–Giemsa – 100x). A) Refractory anemia – showing dyserythropoiesis with cytoplasmic vacuolation. B) Refractory thrombocytopenia – showing dysmegakaryopoiesis with multinucleation.

Figure 2

A) Leishman Stain (×100 magnification). Showing dyserythropoiesis. B) May–Grunwald Giemsa Stain (×100 magnification). Arrow showing binucleate erythroblast. C) Leishman Stain (×200 magnification). Showing multinucleate erythroblast and erythroid dysplasia.

Figure 3

Refractory anemia with ringed sideroblasts (RARS). A) Peripheral blood smear (Wright–Giemsa – 100x). Occasional macro-ovalocytes seen. B) Bone marrow biopsy specimen (H&E stain – 100x). Erythroid hyperplasia with immature erythroid cells. C) Iron stain – 100x. With ringed sideroblasts.

Figure 4

Refractory cytopenia with multilineage dysplasia (RCMD). Bone marrow aspirate (Wright–Giemsa stain – 100x). Erythroid precursors with nuclear irregularity and myeloid precursors with hypogranulation and hyposegmentation.

Figure 5

Refractory anemia with excess blasts (RAEB). Bone Marrow (A, B) Aspirate (Wright–Giemsa – 100x) showing blasts, RAEB-1. C) Aspirate (Wright–Giemsa – 100x) Blasts with Auer rods, RAEB-2. D) Biopsy (H&E stain – 40x), Abnormal localization of immature precursors (ALIP).

Figure 6

Myelodysplastic syndrome with isolated del (5q). A, B) Bone marrow aspirate (40x and 100x). Hypolobated megakaryocyte seen. C, D) Bone marrow biopsy – (10x and 40x – H&E stain). Hypercellular bone marrow with myeloid proliferation associated with hypolobated or nonlobated megakaryocytes.

Figure 7

Childhood myelodysplastic syndrome. Bone marrow biopsy (H and E – 100X). Dysplastic megakaryocytes.