Learn about the three most important lines of latitude on Earth - the equator, Tropic of Cancer, and Tropic of Capricorn. Learn about the three most important lines of latitude on Earth - the equator, Tropic of Cancer, and Tropic of Capricorn.
General Discussion. Hairy cell leukemia (HCL) is a rare type of blood cancer characterized by abnormal changes in white blood cells known as B lymphocytes. The bone marrow creates too many of these defective cells, known as hairy cells because of the thin hair-like projections found on their surface.
This means that Hairy cell leukemia, or a subtype of Hairy cell leukemia, affects less than 200,000 people in the US population. Ophanet, a consortium of European partners, currently defines a condition rare when it affects 1 person per 2,000. They list Hairy cell leukemia as a rare disease.