Summary
Acute Non Lymphoblastic Leukemia (ANLL) or Acute Myelogenous Leukemia (AML) refers to a heterogeneous group of hematological diseases with similar morphology. It can be defined as a disseminated clonal proliferation of immature cells that resemble normal hematopoietic progenitor cells. The incidence in children (<15 years) is lower than 1 in 100,000. Eight morphologic sub-types of ANLL (M0-M7) associated with different characteristics and outcome have been defined by criteria of the French-American-British (FAB) cooperative group. Symptoms are mainly non-specific, including fever, malaise, palor, hemorrhages, although 1/3 of patients present also with some specific symptoms due to extra-medullar (skin, CNS, retro-ocular region, subcutaneous cell tissue) involvement. Main laboratory findings include leukopenia or leukocytosis with peripheral blasts, anemia and thrombocytopenia. The etiology is unknown but many genetic abnormalities have been identified in blast cells and are considered to play a major role in leukemic transformation and proliferation. Point mutations, translocations or deletions may result in gene amplification, loss of suppressor genes and their products, or production of abnormal proteins. Some constitutional syndromes may also predispose also ANLL, the most important being Down Syndrome. Thus, the risk of developing ANLL is 20 times higher in children with Down Syndrome. Some toxic factors and drugs, mainly anti-neoplastic drugs, are involved in the development of secondary or therapy-related ANLL. Treatment consists of intensive chemotherapy (antracyclines and ARA-C based regimens) followed by stem-cell transplantation. As mortality due to complications is still high, supportive care plays an important role in ANLL management. *Author: Dr A. Verdeguer (November 2003)*.
