Myeloproliferative neoplasms

17 Myeloproliferative neoplasms


Myeloproliferative neoplasms are clonal hematopoietic stem cell diseases with expansion, excessive production, and overaccumulation of erythrocytes, granulocytes, and platelets individually or in some combination.


The World Health Organization classification of tumors of the hematopoietic and lymphoid tissues has divided these disorders into four major categories:



1. Chronic myelogenous leukemia, BCR-ABL1+ (CML)


2. Polycythemia vera (PV)


3. Essential thrombocythemia (ET)


4. Primary myelofibrosis (PMF)


These neoplasms have common clinical features, laboratory findings, and pathogenetic similarities (Table 17-1).



TABLE 17-1 Laboratory Features of Myeloproliferative Neoplasms

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Chronic myelogenous leukemia, BCR-ABL1 positive



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FIGURE 17–1A Peripheral blood. Note immature basophils and eosinophil (Original size ×500).


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FIGURE 17–1B Peripheral blood. Arrow shows a micromegakaryocyte.


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FIGURE 17–1C BM ×500. A spectrum of granulocytes, including multiple myelocytes, bands, and an immature basophil.


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FIGURE 17–1D BM ×500. Multiple eosinophils, some of them immature.








Note:


BCR-ABL positivity must be present for diagnosis.





Morphology



Peripheral blood:

Chronic phase*



Leukocytes




Marked leukocytosis (12-1000 × 109/L)


• Spectrum of myeloid cells with a predominance of myelocytes and segmented neutrophils

• Myeloblasts <5%

• ± Pseudo-Pelger-Huët cells

• Basophilia

• Eosinophilia

• ± Monocytosis

• Leukocyte alkaline phosphatase (LAP) markedly decreased (Figure 17-2)


Erythrocytes




Normal or decreased in number



Platelets




• Normal or increased


• ± Circulating micromegakaryocytes



Bone marrow:



• Hypercellular with expansion of granulocyte pool


• Myeloid:Erythroid (M:E) ratio increased


• Myeloblasts <5%


• Megakaryocytes normal to increased; may be immature and/or atypical


• ± Pseudo-Gaucher cells (see Figure 22-1A)


• ± Sea blue histiocytes (see Figure 22-5A)



Leukocyte alkaline phosphatase

Related posts:

Hematopoiesis Precursor lymphoid neoplasms Variations in size and color of erythrocytes Erythrocyte maturation Variations in shape and distribution of erythrocytes Diseases affecting erythrocytes

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Jun 12, 2016 | Posted by in HEMATOLOGY | Comments Off on Myeloproliferative neoplasms

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