Myeloproliferative Neoplasms and Myelodysplastic Syndrome Lecture

Vocabulary practice flashcards covering Myeloproliferative Neoplasms (MPNs), CML, PV, ET, PMF, and Myelodysplastic Syndromes (MDS) based on the lecture materials.

Myeloproliferative Neoplasms (MPNs)

Hematopoietic disorders caused by genetic mutations in hematopoietic stem cells that result in the expansion, excessive production, and accumulation of erythrocytes, granulocytes, and platelets.

Philadelphia chromosome

The derivative $22q-$ chromosome generated by a reciprocal chromosomal translocation between the long arms of chromosome $9$ (containing the ABL1 gene) and chromosome $22$ (containing the BCR gene).

BCR-ABL1

A fusion gene located on the Philadelphia chromosome that encodes a protein tyrosine kinase (TK) with constitutive kinase activity, causing abnormal cell cycling and increased proliferation.

Chronic Myelogenous Leukemia (CML) Age Group

Occurs at all ages but is most frequently seen in individuals aged $46$ to $53$ years old.

Chloromas

Greenish extramyeloid masses that appear green on fresh incision, presumably due to the presence of the myeloid enzyme myeloperoxidase.

Initial Phase of CML

The early phase of the disease lasting $3$-$5$ years, where blasts are usually $< 10\%$ of the peripheral blood WBCs.

Accelerated Phase of CML

A phase that may precede blast transformation, characterized by blasts between $10\%$ and $19\%$ in the peripheral blood.

Blast Crisis (Acute CML)

A phase characterized by the appearance of primitive blast cells similar to acute leukemia, where blasts are $\ge 20\%$ in the peripheral blood.

Leukocyte Alkaline Phosphatase (LAP) score in CML

The score is typically moderately decreased (\downarrow) in patients with CML.

Panmyelosis

A characteristic of Polycythemia Vera (PV) involving a simultaneous increase in erythrocytes, granulocytes, and platelets in the bone marrow and peripheral blood.

JAK2 (Janus Kinase 2) Mutation

A mutation found in $65\%$ to $97\%$ of PV cases and approximately $55\%$ of ET cases; it allows for erythropoietin-independent production of RBCs.

Plethora

The hallmark clinical sign of Polycythemia Vera.

Essential Thrombocythemia (ET)

A chronic clonal MPN characterized by increased production of megakaryocytes in the bone marrow and a platelet concentration in the blood $> 450 \times 10^9/L$.

Pseudohyperkalemia

A lab finding that may occur during the preparation of serum in patients with Essential Thrombocythemia due to high platelet counts.

Primary Myelofibrosis (PMF) Classic Triad

The clinical findings of Myelofibrosis, Extramedullary hematopoiesis, and Leukoerythroblastosis with the presence of dacryocytes.

Dacryocytes

Teardrop-shaped erythrocytes typically seen in Primary Myelofibrosis.

Transforming Growth Factor B (TGF-B)

The most important cytokine involved in the pathogenesis of fibrosis in Primary Myelofibrosis.

Myelodysplastic Syndromes (MDS)

A group of acquired clonal hematologic disorders characterized by progressive cytopenias reflecting defects in erythroid, myeloid, and/or megakaryocytic maturation.

Dyserythropoiesis

Abnormal RBC development evidenced by features such as precursors with more than one nucleus, abnormal nuclear shapes, ring sideroblasts, and basophilic stippling.

Dysmyelopoiesis

Abnormal myeloid development characterized by nuclear-cytoplasmic asynchrony, hyposegmentation (Pelger-Hu\u00ebt-like), or abnormal granulation.

Dysmegakaryopoiesis

Abnormal megakaryocyte development characterized by giant platelets, circulating micromegakaryocytes, or large mononuclear megakaryocytes.

RAEB-1 (WHO classification)

Refractory anemia with excess blasts-1, characterized by $5\%$ to $9\%$ blasts in the bone marrow or $2\%$ to $4\%$ blasts in the peripheral blood.

RAEB-2 (WHO classification)

Refractory anemia with excess blasts-2, characterized by $10\%$ to $19\%$ blasts in the bone marrow and $5\%$ to $19\%$ blasts in the peripheral blood.

Myelodysplastic Syndrome with Isolated del(5q)

A syndrome affecting predominantly women (median age $67$) characterized by refractory anemia, hypolobulated megakaryocytes, and erythroid hypoplasia.

Chronic Myelomonocytic Leukemia (CMML)

A disorder in the MDS/MPN category characterized by persistent monocytosis of $> 1.0 \times 10^9/L$ and absence of the BCR-ABL1 fusion gene.

Juvenile Myelomonocytic Leukemia (JMML)

A clonal disorder affecting children from $1$ month to $14$ years old, showing a strong association with neurofibromatosis type $1$.