Chronic myeloid leukemia
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Chronic myeloid leukaemia, abbreviated CML, is a type of myeloproliferative neoplasm. It is also known as chronic myelogenous leukemia.
It is driven by the bcr-abl fusion protein, detectable cytogenetically as the Philadelphia chromosome. It is a leukemia in that the fusion protein drives granulopoiesis (and less commonly megakaryopoiesis), resulting in marked peripheral blood leucocytosis.
General
- Adults - usually 50s or 60s.
Clinical - commonly:[1]
- Leukocytosis - neutrophils, myelocytes, metamyelocytes, +/-eosinophilia, +/-basophilia.
Progression:
- Chronic phase - potentially curable.
- Accelerated phase.
- Blast crisis.
Treatment:
- Imatinib and other tyrosine kinase inhibitors
Notes:
- Myeloblast (common granulocyte precursor) -> promyelocyte -> metamyelocyte -> myelocyte -> band -> mature myelocyte.[2]
Microscopic
Features:
- Bone marrow with too many granulocytes/granulocyte precursors.
- Granulocyte precursors:[2]
- Myeloblast (common granulocyte precursor) ~ 90% nucleus, multiple nucleoli.
- Should be less than 10%.
- Promyelocyte (committed to a specific linage (neutrophil, basophil or eosinophil)) - dia. 2x mature, 40-50% nucleus, one nucleolus.
- Metamyelocyte - dia. 2x mature, 30-40% nucleus, no nucleolus.
- Myelocyte - dia. 1x mature, 50-60% nucleus - kidney bean shape, no nucleolus.
- Band - dia. 1x mature, 30-40% nucleus - C shape/irregular, no nucleolus.
- Myeloblast (common granulocyte precursor) ~ 90% nucleus, multiple nucleoli.
- Granulocyte precursors:[2]
IHC
Rarely required. CML may transform into a blast phase, typically myeloid blasts, but lymphoblasts may also be seen. These blasts are typically CD34 and/or CD117 positive. The myeloid blasts will express myeloid markers and the lymphoblasts will shows lymphoid markers.
Molecular
- t(9;22) BCR-ABL - required for diagnosis.
- May be found in other leukemias.
See also
References
- ↑ Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 336. ISBN 978-1416054542.
- ↑ 2.0 2.1 URL: http://commons.wikimedia.org/wiki/File:Hematopoiesis_%28human%29_diagram.png. Accessed on: 14 January 2012.