Difference between revisions of "Myelodysplastic syndromes"
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*CD34 - (myeloid) progenitor/precursor cells. | *CD34 - (myeloid) progenitor/precursor cells. | ||
*CD117 - (myeloid) progenitor/precursor cells, mast cells. | *CD117 - (myeloid) progenitor/precursor cells, mast cells. | ||
* | *Tryptase - mast cells, immature basophils. | ||
**Uncommonly done. | **Uncommonly done. | ||
*CD61 - megakaryocytes. | *CD61 - megakaryocytes. | ||
Revision as of 16:57, 29 May 2011
Myelodysplastic syndromes, abbreviated MDS, can be thought of a pre-leukemia/pre-lymphoma.
They should not be confused with myeloproliferative neoplasms.
Overview
Lab fidnings
- +/-Anemia.
- +/-Neutropenia.
- +/-Thrombocytopenia.
Notes:
- MDS is usu. an incidental finding, i.e. it is asymptomatic.
Associations
Syndromes associated with MDS:[1]
- Fanconi syndrome.
- Diamond-blackfan syndrome.
- Shwachman-diamond syndrome.
Diagnostic criteria
All of the following:[1]
- At least 6 months + persistent.
- Dysplasia.
- Cytologic:
- Need >=10% abnormal.
- Cytogenetic.
- Cytologic:
- All other causes excluded.
- Blast percentage <20%.
- If >=20% = leukemia.
- Criteria blast percentage:
- Bone marrow: 500 nucleated cells - includes erythroblasts, plasma cells; excludes megakaryocytes.
- Peripheral blood: 200 leukocytes.
Required clinical information
- CBC - usu. macrocytic anemia.
- Rx - may be Rx effect.
- Peripheral blood film.
- Clinical history (symptoms/presentation/PMHx).
Laboratory work-up
- H&E stain.
- Giemsa/Wright stain.
- Iron stain.
- Gomori silver stain.
DDx of MDS
- Nutritional deficiency.
- Vitamin B12.
- Folate.
- Toxic exposures.
- Rx.
- G-CSF.
- Biologic agents.
- Heavy metals.
- Chemotherapy.
- Rx.
- Infections.
- Parovirus B19.
- Other.
- Paroxysmal nocturnal hemoglobinuria (PNH).[2] (???)
- Congenital hematopoietic disorder.
- Congenital dyserythropoietic anemia.
Bone marrow specimens
Normal
- Age (years) ~ percentage of fat.
- Example 80 years old has ~ 80% fat in marrow space.
Erythroblasts:
- Typically away from bone.
Megakaryocytes:
- Alone - not in clusters.
- Not close to bone.
Myeloid cells:
- Adjacent to bone.
Histologic features
- Auer rods - used to be diagnostic of MDS regardless of blast count.
Dyserythropoiesis
- Abnormal RBC formation.
Histology
Nuclear
Features:[1]
- Nuclear budding.
- Intranuclear bridging (nuclei fail to separate post-division).
- Multinucleation.
- Megablastoid change.
- May be hard to see.
- Karyorrhexis (nuclear fragmentation).
Cytoplasmic
Features:[1]
- Ring sideroblasts.
- Rim of RBC has ring of iron.
- Vacuolization.
Dysgranulopoiesis
- Abnormal granulocyte formation.
Histology
Features:[1]
- Nuclear hypolobation (pseudo-Pelger-Huet).
- Hypersegmentation.
- May be seen in vitamin B12 deficiency, Rx.
- Cytoplasmic hypogranulation.
- Pseudo-Chediak-Higashi granules.
- Small size.
Dysmegakaryocytopoiesis
- Abnormal megakaryocyte formation.
Histology
Features:[1]
- Micromegakaryoctes with ypolobated nuclei.
- Non-lobated nuclei of any size.
- Multiple widely separated nuclear lobes.
IHC
Typical IHC in work-up of MDS:
- CD34 - (myeloid) progenitor/precursor cells.
- CD117 - (myeloid) progenitor/precursor cells, mast cells.
- Tryptase - mast cells, immature basophils.
- Uncommonly done.
- CD61 - megakaryocytes.
- CD42b - megakaryocytes.
- CD20 - B cells.
- CD3 - T cells.
- Glycophorin A - erythroid cells.
- Glycophorin C - erythroid cells.
Notes:
- Other megakaryocyte markers: factor VIII, vWF. (???)