B Acute Lymphoblastic Leukemia with Intrachromosomal Amplification of Chromosome 21

**Semantic type:** Neoplastic Process

**Definition:** B acute lymphoblastic leukemia characterized by amplification of a portion of chromosome 21. It usually occurs in children and is associated with an adverse prognosis.

**Synonyms:** - B Acute Lymphoblastic Leukemia with iAMP21 - B-ALL with iAMP21 - B-Acute Lymphoblastic Leukemia with Intrachromosomal Amplification of Chromosome 21