Hairy Cell Leukemia

Hairy cell leukemia is a rare type of blood cancer that happens when your bone marrow makes abnormal B-cells (B lymphocytes). These are a type of white blood cells that fight infections. The name of the condition comes from the tiny hair-like protrusions on the abnormal B-cells, which pathologists can see when they look at the cells under a microscope.

You have B lymphocytes in your bone marrow, lymph nodes and spleen. Hairy cell leukemia symptoms happen when your normal B lymphocytes change into abnormal ones. When that happens:

• Abnormal cells in your bone marrow act like weeds taking over a vegetable garden. They take up so much space in your bone marrow that there’s no room for healthy white blood cells, red blood cells and platelets.
• Cells in your lymph nodes and spleen divide and multiply, making them swell.
• Cells in your bloodstream may spread to your liver, causing damage that leads to ascites (fluid buildup in your belly).

How common is hairy cell leukemia?

Hairy cell leukemia is a rare condition that affects 1 in 100,000 people in the U.S.

The condition affects men and people assigned male at birth (AMAB) more than women and people assigned female at birth (AFAB). It’s more common in people who are white than people in other ethnic groups.