CLL also known as CLL/SLL or chronic lymphocytic leukemia/small lymphocytic lymphoma is a blood cancer, specifically of a type of white blood cell called the B-lymphocyte. It is the most common leukemia in adults in North America. In CLL there is a progressive accumulation of too many incompetent, mature lymphocytes, which are usually monoclonal or genetically identical.
To confuse matters, besides being a type of leukemia, it is also classified as a type of non-Hodgkin’s Lymphoma (NHL).
So CLL is both a leukemia and a lymphoma at the same time.
SLL is best understood as a different stage of CLL where there are not a significant number of cancer cells in the blood stream.
Originally published in The CLL Tribune Q3 2015