Chronic lymphocytic leukemia

Also known as CLL. An indolent B-cell leukemia more common in elderly population. Characteristic immunophenotype (dimCD20+, CD19+, CD5+, CD23+, CD10- monotypic dim kappa or dim lambda B-cells). The disease has two forms: CLL if it's in the blood (hence, "Leukemia") and SLL (Small Lymphocytic Lymphoma) if it's in the tissue such as lymph nodes (hence, "Lymphoma"). Mnemonic: As opposed to Acute Lymphoblastic Leukemia (ALL) which are "immature" cells and more common in "pediatric" (less mature) population, CLL is comprised of "mature" lymphocytes and predominantly seen in elderly (more mature) population.