Myelodysplastic syndrome pathophysiology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Nawal Muazam M.D.[2]
Overview
Myelodysplastic syndrome comprises a heterogeneous group of clonal bone marrow disorders.[1] Cytogenetic abnormalities involved in the pathogenesis of myelodysplastic syndrome include isolated deletion of 5q, monosomy 7, and monosomy 8.[1] Myelodysplastic syndrome is associated with Fanconi syndrome, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome.[2] There are no characteristic findings of myelodysplastic syndrome on gross pathology. On microscopic histopathological analysis, dyserythropoiesis, dysgranulopoiesis, and dysmegakaryocytopoiesis are findings of myelodysplastic syndrome.[1]
Pathogenesis
Myelodysplastic syndrome comprises a heterogeneous group of clonal bone marrow disorders characterized by:[3]
- Various degrees of pancytopenia
- Morphological and functional abnormalities of hematopoietic cells
- Increased risk of transformation into acute myeloid leukemia
Genetics
Cytogenetic abnormalities involved in the pathogenesis of myelodysplastic syndrome include:[1]
- Isolated deletion of 5q
- Isolated deletion of 17p
- Monosomy 7
- Monosomy 8
Associated Conditions
Myelodysplastic syndrome is associated with:[2]
Gross Pathology
There are no characteristic findings of myelodysplastic syndrome on gross pathology.
Microscopic Pathology
On microscopic histopathological analysis, characteristic findings of myelodysplastic syndrome include:[1]
- Dyserythropoiesis (abnormal red blood cell formation)
- Dysgranulopoiesis (abnormal granulocyte formation)
- Dysmegakaryocytopoiesis (abnormal megakaryocyte formation)
Dyserythropoiesis
Nuclear Features
- Nuclear budding
- Intranuclear bridging (nuclei fail to separate post-division)
- Multinucleation
- Megablastoid changes (may be difficult to observe)
- Karyorrhexis (nuclear fragmentation)
Cytoplasmic Features
- Ring sideroblasts (red blood cells are surrounded by a ring of iron)
- Vacuolization
Dysgranulopoiesis
Nuclear Features
- Nuclear hypolobation (pseudo Pelger-Huët)
- Nuclear hypersegmentation
Cytoplasmic Features
- Cytoplasmic hypogranulation
- Pseudo-Chediak-Higashi granules
- Small cytoplasmic size
Dysmegakaryocytopoiesis
Nuclear Features
- Micromegakaryoctes with hypolobated nuclei
- Non-lobated nuclei of any size
- Multiple widely separated nuclear lobes
Immunohistochemistry
On immunohistochemistry, characteristic findings of myelodysplastic syndrome include:
- CD34 positive- (myeloid) progenitor/precursor cells
- CD117 positive- (myeloid) progenitor/precursor cells, mast cells
- Tryptase positive- mast cells, immature basophils
- CD61 positive- megakaryocytes
- CD42b positive- megakaryocytes
- CD20 positive- B cells
- CD3 positive- T cells
- Glycophorin A positive- erythroid cells
- Glycophorin C positive- erythroid cells
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Cytogenetics of myelodysplastic syndromes. Librepathology (2015). http://librepathology.org/wiki/index.php/Myelodysplastic_syndromes. Accessed on December 8, 2015
- ↑ 2.0 2.1 Associations of myelodysplastic syndromes. Librepathology (2015). http://librepathology.org/wiki/index.php/Myelodysplastic_syndromes. Accessed on December 8, 2015
- ↑ Corrêa de Souza, Daiane; de Souza Fernandez, Cecília; Camargo, Adriana; Apa, Alexandre Gustavo; Sobral da Costa, Elaine; Bouzas, Luis Fernando; Abdelhay, Eliana; de Souza Fernandez, Teresa (2014). “Cytogenetic as an Important Tool for Diagnosis and Prognosis for Patients with Hypocellular Primary Myelodysplastic Syndrome”. BioMed Research International. 2014: 1–10. doi:10.1155/2014/542395. ISSN 2314-6133.
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