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35 Cards in this Set

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Define Myelodysplastic Syndromes
A group of Myeloid Stem Cell Neoplasms characterized by:
1. maturation defects (Dysplasia) resulting in INEFFECTIVE HEMATOPOIESIS
2. increased risk of transformation to AML
How is Myelodysplastic Syndrome different from CML?
Instead of producing Mature White Cells that go into the blood, it inhibits Mature myeloid cells from going into the blood = Ineffective Hematopoiesis
What is the etiology of Primary Myelodysplastic Syndromes?
Unknown
What is the etiology of Secondary Myelodysplastic Syndromes?
Radiation or Chemotherapy
What genetic mutations are common in Myelodysplastic Syndromes?
-Monosomy 5, del 5q
-Monosomy 7, del 7q
-Trisomy 8
-del 20q
What is a characteristic feature of the pathogenesis of Myelodysplastic Syndromes?
Increased Apoptosis --> causes Ineffective Hematopoiesis = cells are being formed, but they are dying so quickly that they don't produce mature progeny
What blood pathologies are seen in Myelodysplastic Syndromes?
1. Pancytopenia = cells are dying via Apoptosis

2. Dysplastic Neutrophils = Pseudo-Pelger-Huet cells = Bilobed neutrophils that have perfectly round lobes/nuclei
What pathologies are seen in the Bone Marrow in Myelodysplastic Syndrome?
1. Panhypercellular = cells are proliferating but are also undergoing Apoptosis rapidly
2. Dysplastic Red Cell Precursors = Ring Siderblasts
3. "Pawn ball" Megakaryocytes = dysplastic megakaryocytes = separated nuclear lobes
4. Bone Marrow blasts < 20%
What is a Pseudo-Pelger-Huet Cell? What disease?
Neutrophil with only 2 nuclear lobes = "aviator glasses" nuclei

Myelodysplastic Syndrome
What are Ring Sideroblasts?

What disease?
Erythroblasts with blue-green granules localized around the nucleus = iron trapped within Mitochondria surrounding the nucleus

Myelodysplastic Syndrome
What are "Pawn ball" Megakaryocytes?

What disease?
Atypical megakaryocytes with multiple separates nuclear lobes/nuclei = due to abnormal endoreduplication

Myelodysplastic Syndrome

**normal megakaryocytes have a single multilobated nucleus without separation of lobes
What are the clinical features of Myelodysplastic Syndrome?
1. Elderly age (>60 yoa)
2. Symptoms of Pancytopenia
-Fatigue = anemia
-Bleeding = Thrombocytopenia
-Fever and Infections = Neutropenia
What is the survival time for Primary Myelodysplastic Syndrome?
9-29 months
What is the typical survival period for Secondary Myelodysplastic Syndrome?
4 - 8 months
What is the main cause of death in Myelodysplastic Syndrome?
Transformation to AML --> occurs in 10-40% of patients
What are the treatments for Myelodysplastic Syndrome? Why is this a problem?
Bone Marrow Transplant
-most patients are >60 yoa
-Elderly patients do not respond well to transplants

Supportive Therapy
-transfusions
-Antibiotics
What is the definition of Langerhans Cell Histiocytosis?
Neoplastic proliferation of Langerhans cells, a subtype of APC dendritic cell usually found in the skin
What is the only known pathogenesis property of Langerhans Cell Histiocytosis?
Neoplastic histiocytes express Chemokine Receptor CCR7

**many tissues make the ligand for this receptor, which might explain the broad range of organs where these cells can be found
What are the 4 histologic properties of Langerhans cell histiocytosis?
1. Sheets of histiocytes
2. Admixed Eosinophils
3. S100 + = stain + for this intermediate filament
4. Birbeck granules
Birbeck granules are pathognomic for what disease?
Langerhans Cell Histiocytosis
This is the most common Langerhans Cell Histiocytosis and also has the best prognosis
Eosinophilic granuloma
Histiocytosis with Unifocal lytic lesions in bone, most commonly occurs in adults and adolescents

Bone pain and pathologic fractures are common
Eosinophilic Granuloma
Histiocytosis in which a lung lesion is common in smokers and regresses when the patient stops smoking
Eosinophilic Granuloma
Histiocytosis that occurs in children and typically affects multiple organs, excluding the Bone Marrow
Hand-Schuller-Christian Disease
Histiocytosis that occurs in children that affects many organs, including the bone marrow
Letterer-Siwe Disease
What are the symptoms of Hand-Schuller-Christian Disease?
Classic Triad:
1. Cystic skull defects
2. Diabetes insipidus due to invasion of Posterior Pituitary
3. Exophthalmos due to infiltration of the orbit
Rapidly fatal histiocytosis of infants and small children.

Characterized by hepatosplenomegaly, lymphadenopathy, pancytopenia, pulmonary involvement, and recurrent infections as a result of widespread histiocytic proliferation
Letterer-Siwe Disease
Pseudo-Pelger-Huet cell = neutrophil with only 2 nuclear lobes = "aviator glasses" nuclei


Myelodysplastic Syndromes
What is the arrow pointing at?

What disease?
Ringed Siderblasts = Prussian blue stain = Erythroblasts with iron trapped within mitochondria

Myelodysplastic Syndrome
What is the arrow pointing at?

What is the disease?
Atypical Megakaryocytes = "pawn ball" megakaryocytes

Myelodysplastic Syndrome
What are these arrows pointing at?

What disease?
Langerhans Cell Histiocytosis
-sheets of histiocytes within a lymph node
-Histiocytes have oval/round nuclei with vesicular chromatic
-some have linear nuclear grooves
-cytoplasm is abundant and eosinophilic
What disease?
Birbeck granules = "tennis racket"

Langerhans cell Histiocytosis
What is the arrow pointing at?

What disease is this pathognomic for?
B. CML
-
C. Lymphocytosis
-
A child presents with exophthalmos, diabetes insipidus, and cystic defects in the skull
Hand-Schuller-Christian Disease