Acute megakaryoblastic leukemia | |
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AML-M7, Blast cells of acute megakaryoblastic leukemia in the bone marrow. Clasmatosis of the cytoplasm of atypical cells is observed. Some of the cells produce and release platelets | |
Specialty | Hematology, oncology |
Acute megakaryoblastic leukemia (AMKL) is life-threatening leukemia in which malignant megakaryoblasts proliferate abnormally and injure various tissues. Megakaryoblasts are the most immature precursor cells in a platelet-forming lineage; they mature to promegakaryocytes and, ultimately, megakaryocytes which cells shed membrane-enclosed particles, i.e. platelets, into the circulation. Platelets are critical for the normal clotting of blood. While malignant megakaryoblasts usually are the predominant proliferating and tissue-damaging cells, their similarly malignant descendants, promegakaryocytes and megakaryocytes, are variable contributors to the malignancy.[1]
AMKL is commonly regarded as a subtype of acute myeloid leukemia (AML). More formally, it is classified under the AML-M7 category of the French-American-British classification[2] and by the World Health Organization of 2016 in the AML-Not Otherwise Specified subcategory.[3]
Acute megakaryoblastic leukemia falls into three distinct groups which differ in underlying causes, ages of presentation, responses to therapy, and prognoses. These groups are: AMKL occurring in young children with Down syndrome, i.e. DS-AMKL; AMKL occurring in children who do not have Down syndrome, i.e. non-DS-AMKL (also termed pediatric acute megakaryoblastic leukemia or pediatric AMKL); and AMKL occurring in non-DS adults, i.e. adult-AMKL.[1] AMKL, while rare, is the most common form of AML in DS-AMKL, occurring ~500-fold more commonly in Down syndrome children than in children without Down syndrome; non-DS-AMKL and adult-AMLK are rare, accounting for <1% of all individuals diagnosed as in the AML-M7 category of leukemia.[4]