Hairy Cell Leukemia

Hairy Cell Leukemia is a rare type of cancer that affects the blood and bone marrow, which are parts of the body's system for making blood cells. It involves the abnormal growth of a specific kind of white blood cell called a B lymphocyte, which gets its name from the hair-like projections seen under the microscope. This disease mainly impacts the immune system and the body's ability to fight infections. People with this condition often experience symptoms like fatigue, easy bruising or bleeding, and an enlarged spleen. The abnormal cells crowd out normal blood cells, leading to low counts of red cells, white cells, and platelets. Diagnosis usually involves blood tests and bone marrow examination. Treatment can help control the disease and improve symptoms.

Hairy Cell Leukemia is a chronic B-cell lymphoproliferative disorder characterized by the clonal expansion of abnormal mature B lymphocytes with distinctive cytoplasmic projections. It is caused by activating mutations in the BRAF gene, most commonly the V600E mutation, leading to constitutive activation of the MAP kinase pathway. The disease primarily affects the bone marrow, spleen, and peripheral blood, resulting in pancytopenia, splenomegaly, and increased susceptibility to infections. The abnormal cells express markers such as CD19, CD20, CD22, CD25, CD103, and annexin A1. Clinically, patients present with symptoms related to cytopenias and splenic enlargement. The disease is indolent but progressive without treatment and requires differentiation from other B-cell malignancies.