B Lymphoblastic Leukemia/Lymphoma

**Semantic type:** Neoplastic Process

**Definition:** A neoplasm of lymphoblasts committed to the B-cell lineage, typically composed of small to medium-sized blast cells. When the neoplasm involves predominantly the bone marrow and the peripheral blood, it is called B acute lymphoblastic leukemia. When it involves nodal or extranodal sites, it is called B lymphoblastic lymphoma. (WHO, 2001)

**Synonyms:** - B-Cell Lymphoblastic Leukemia/Lymphoma - B-Lymphoblastic Leukemia/Lymphoma - Precursor B Lymphoblastic Leukemia/Lymphoma - Precursor B-Lymphoblastic Lymphoma/Leukemia