MDS1 Flashcards
2 main features that characterize myelodysplastic syndrome (MDS
- ineffective hematopoiesis:
2. increased risk of transformation to acute leukemia:
Ineffective hematopoiesis in MDS
○ The clone (hematopoietic stem cells) is not able to make normal functioning blood cells.
○ Cells often die before leaving the marrow, and usually look abnormal (dysplastic)
MDS increased risk of transformation to acute leukemia
hematopoietic stem cell clone slowly acquires enough abnormalities → outright AML
2 clinical scenarios of MDS
- Primary (idiopathic) MDS
2. Secondary / therapy-related (t-MDS)
Primary (idiopathic) MDS
- Type of onset?
- Age group:
- Median age of dx:
- Incidence:
○ Insidious onset
○ Usually people >50
○ Median age of dx:70
○ Incidence: 3-5 cases/100,000 persons per year
Secondary / therapy-related (t-MDS)
- Type of onset?
- types of therapy leading to MDS
- 2-8 years latency
- use of alkylating agent
- use of topo II
- Exposure of active marrow to ionizing radiation
List 3 different types of tests that could be performed to make a diagnosis of MDS.
1) Morphologic evidence of dysplasia in marrow
2) Increased myeloblasts, but less than 20% of blood and marrow cells
3) Presence of a clonal cytogenetic abnormality
Morphologic evidence of dysplasia in marrow for MDS
Dyshematopoiesis: > 10% of cell are dysplastic
- Dyserythropoiesis
- Dysgranulopoiesis
- Dysmegakaryopoiesis
Dyserythropoiesis
RBC precursors with nuclear budding, irregularly-shaped nuclei, lack of coordination between nuclear and cytoplasmic maturation, increased ring sideroblasts
Dysgranulopoiesis
Nuclear hypolobation of mature neutrophils, including neutrophils with bilobed nuclei called pseudo-Pelger-Huet cells, also cytoplasmic hypogranularity of neutrophils
Dysmegakaryopoiesis
Megakaryocytes with hypolobated or non-lobated nuclei, often hyperchromatic nuclei, megakaryocytes often of small size
4 possible causes of secondary myelodysplasia that might mimic MDS.
- Certain drugs, including many chemotherapeutic drugs
- use of alkylating agent
- use of topo II
- ionizing radiation - Vitamin deficiency (B12, folate, ect)
- Viral infection
- Toxin exposure (heavy metals such as arsenic)
LOW GRADE MDS:
- Myeloblasts are not increased in frequency
- Refractory Cytopenia with Unilineage Dysplasia (RCUD): good prognosis
- Refractory Cytopenia with Multilineage Dysplasia (RCMD): worse prognosis
HIGH GRADE MDS
- Myeloblasts are increased in frequency, (less than 20%)
- Refractory Anemia with Excess Blasts-1 (RAEB-1) : dismal prognosis
- Refractory Anemia with Excess Blasts-2 (RAEB-2): VERY dismal prognosis
MDS vs. MPNs:
- source of disease
MDS: marrow is REPLACED by a malignant clone, derived from a transformed stem cell or progenitor cell
MPS: Clonal hematopoietic NEOPLASM arising from a transformed hematopoietic stem cell
MDS vs. MPNs:
- onset
Both insidious