Maturation disorders and signs of dysplasia

General notes:

Maturation disorders are all morphological alterations of cells, that differ from the regular stage of maturation. Numerous reasons can cause maturation disorders, e.g. inflammatory-infectious diseases, drugs (G-CSF, immunosuppressive and/or cytostatic drugs, cotrimoxazole, etc.), lack of trace elements, lack of vitamin B12- or folic acid , exposure to heavy metals (e.g. lead), myelodysplastic syndromes and others more.

Those morphological alterations are called dysplasia or signs of dysplasia, that are typically seen in myelodysplastic syndromes (MDS). To qualify as a criterion for myelodysplastic syndromes, at least 10% of the cells of one myeloid cell lineage must be affected. Since these alterations are oft discrete, the quality of the blood film and the staining must be excellent.

Signs of dysplasia in myelodysplastic syndromes:

Dyserythropoiesis

• Nucleus:
  • Nuclear eversion and nuclear pinch-off
  • Internuclear bridges
  • Karyorrhexis
  • Two or more nuclei in erythroid precursor cells
  • Megaloblastic nuclei
• Cytoplasm:
  • Vacuolization
  • PAS-positive normoblasts
  • Ringed sideroblasts

Dysgranulopoiesis

• Hypolobulated nuclei (Pseudo-Pelger-Huët)
• Hypersegmentation
• Hypogranular or agranular cytoplasm
• Pseudo-Chediak-Higashi cytoplasm inclusions
• Small or unusual large cells
• Auer rods
• Dimorphic granule in eosinophils (simultaneously eosinophil and basophil)
• Loss of myeloperoxidase

Dysmegakaryopoiesis

• Micromegakaryocytes
• Multinuclear megakaryocytes with clearly separated nuclear fragments
• Hypolobulated and monolobulated nuclei