Hairy cell leukemia (HCL) is a rare type of chronic leukemia, accounting for about 2% of all cases of leukemia. It is characterized by the excessive production of abnormal B lymphocytes (a type of white blood cell) in the bone marrow. These abnormal cells have fine, hair-like projections on their surface, hence the term "hairy cell."
The exact cause of HCL is unknown, but it is believed to involve a mutation in the DNA of the B lymphocytes.
