Medicina: Oncoematologia pediatrica: Leucemia linfoblastica acuta
| English |
| b-cell all |
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| Attestation |
3
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| Definition |
The diagnosis of B-cell leukemia, which accounts for only about 3% of ALL cases, depends on the detection of surface immunoglobulin on leukemic blasts. Lymphoblasts with this phenotype have a distinctive morphology, with deeply basophilic cytoplasm containing prominent vacuoles; this morphologic pattern is designated L3 in the French-American-British (FAB) system. Prominent clinical features include extramedullary lymphomatous masses in the abdomen or head and neck and frequent involvement of the CNS.
The minority of B-cell ALLs with surface Ig expression (most commonly IgM) have L3 morphology; on a bone marrow biopsy they are identical to Burkitts lymphoma. Often these cells have a translocation involving myc on chromosome 8. There is a strong male predominance for B-cell ALL. These leukemias behave differently than the other B-cell leukemias: they have a high mitotic rate, frequently invade the CNS, and often cause abdominal disease. The treatment for B-cell ALL is shorter and more intense than the other earlier B-cell ALLs. Relapses tend to occur within the year following cessation of treatment and are fatal with the exception of treatment by bone marrow transplant.
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| Definition source |
http://www.emedicine.com/ped/topic2587.htm
http://family.georgetown.edu/welchjj/netscut/heme_onc/all.htmlB%20cell%20ALL
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| Context |
Because leukemia is a systemic disease, therapy is primarily chemotherapy-based; different forms of ALL require different approaches for optimal results. For example, B-cell ALL does not respond well to the chemotherapy traditionally used for childhood ALL. However, outstanding results, with EFS estimates of nearly 90%, have been obtained with treatments designed for Burkitt lymphoma, which emphasize cyclophosphamide and the rapid rotation of antimetabolites in high dosages. Thus, B-cell ALL was the first form of ALL to be recognized as a distinct clinical entity on the basis of immunophenotypic and cytogenetic features and the first to be treated by separate protocols designed specifically for this leukemia ´s unique features.
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| Context source |
http://www.emedicine.com/ped/topic2587.htm
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| Subject field |
Pediatric Oncohematology
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| de |
B-ALL
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| it |
B-LLA
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| Reliability code |
3
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