Chronic Lymphocytic Leukemia (CLL)
What Is It?
Chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) is a cancer that occurs when the bone marrow and/or lymph nodes make too many lymphocytes, a type of white blood cell. CLL/SLL usually grows slowly compared to other leukemias and lymphomas, and it may not cause symptoms for some time.
CLL is one of four main types of leukemia. Most people with CLL are middle-aged or older. The disease is very rare in children.