ABSTRACT
B-cell acute lymphoblastic leukemia (B-ALL)/lymphoma is a lymphoproliferative disorder of immature B cells with blastic morphology and specific phenotype. The total white blood cell (WBC) count at the time of diagnosis is the single most powerful clinical predictor of remission induction and duration, and long-term survival for all age groups. Patients with high WBC counts often have extramedullary disease at diagnosis and are at high risk for relapse in the central nervous system and testes. Lymphoblasts are usually medium in size with little variation in their shape and size, increased nuclear/cytoplasmic ratio, finely dispersed nuclear chromatin, inconspicuous nucleoli, and occasionally vacuolated cytoplasm. The bone marrow shows a diffuse and monotonous infiltrate of cells with immature vesicular chromatin, inconspicuous nucleoli, and scanty cytoplasm. Numerous structural and numerical chromosomal aberrations have been identified in B-ALL, many of which are associated with specific disease characteristic and patient outcome.
