Myelodysplastic Syndromes

These conditions involve blood cell dysplasias, which result from reductions in blood cell counts or abnormal production.

Condition	Cause	Lab Findings		Diagnostic Tests	Treatment
		Peripheral Blood	Bone Marrow
Myelodysplastic Syndromes (general)	Usually, translocations	Dysplasia of myeloid cell lines	<20% blasts	Cytogenetic testing Molecular testing Immunological marker (CD marker) testing
Dyserythropoiesis		Oval macrocytes Hypo/micro picture Dimorphic population	Erythroid hyperplasiaAbnormal RBC precursors Multiple nuclei Abnormal nuclear shapes (nuclear budding, nuclear bridging) Uneven staining Ringed sideroblasts Basophilic stippling
Refractory Anemia Form of dyserythropoiesis		Anemia	Bone marrow erythrodysplasia Ringed sideroblasts in >15% of nucleated erythroid precursors Iron mitochondria surrounding >1/3 of nucleus
Dysmyelopoiesis		Neutrophils (>90% showing dysplasia) Uneven cytoplasm staining and basophilia Abnormal granulation (hypo-, hyper-, or agranulation) Abnormal nuclear segmentation (hypo, rarely hyper) pseudo-Pelger-Huet forms Possibly nuclear rings (doughnut-shaped) Nuclear asynchrony Mature, clumped chromatin but immature shape
Dysmegakaryocytopoiesis		Thrombocytopenia (60%) Giant platelets Hypo- or agranulation Micromegakaryocytes with fused granules	Megakaryocytes with abnormal morphology May have small, separated nuclei Micromegakaryocytes and micromegakaryoblasts
Chronic myelomonocytic leukemia (CMML)		Monocytosis >1.0x109/L ↑ leukocytes	<20% blasts Dysplasia in 1+ myeloid cell lines

Differential Diagnosis

Many other conditions can have findings similar to myelodysplastic syndromes.

• Vitamin B12 or folate deficiencies
• Heavy metal exposure
• Fanconi anemia, congenital dyserythropoietic anemia
• Parvovirus B19
• Chemotherapy agents
• Paroxysmal cold hemoglobinuria
• HIV