Myelodysplastic Syndromes

From MedLabWiki

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