Small lymphocytic lymphoma (SLL) is a B-cell lymphoma. Chronic Lymphocytic Leukemia and SLL are essentially the same disease, the only difference being where the cancer primarily occurs: When most of the cancer cells are located in the bloodstream and the bone marrow, the disease is referred to as CLL, although the lymph nodes and spleen are often involved.
When the cancer cells are located mostly in the lymph nodes, the disease is called SLL.
Chronic lymphocytic leukemia (CLL) is a cancer of the lymphocytes (a type of white blood cell) that begins in the stem cells of the bone marrow and then invades the blood. Overtime, CLL may also spread to the lymph nodes and other organs including the liver, spleen and lungs. It occurs when the stem cells that make lymphocytes become out of control and produce increasing amounts of abnormal lymphocytes (also called leukemic cells). Eventually, these abnormal cells replace normal lymphocytes and can crowd out other types of normal blood cells, leading to the features of the condition. The exact underlying cause of CLL/SLL is unknown; however, approximately 5% of affected people have other family members with the condition, which suggests there may be a genetic component in rare cases. The best treatment depends on many factors including the stage of the condition, the age of the affected person, the blood cell counts, whether the CLL has recurred, and the signs and symptoms present in each person.