Hairy Cell Leukemia
Epidemiology and Etiology
Hairy cell leukemia is a rare disorder, most commonly seen in elderly men.
Pathology
Peripheral blood leukocytes have the characteristic “hairy” appearance and are tartrate-resistant acid phosphatase positive.
Flow cytometry is positive for CD20, CD11c, CD103, CD123, cyclin D1, and annexin A1. Genetic sequencing commonly reveals BRAF V600E mutation.Clinical Presentation
Most patients present with malaise and fatigue. Splenomegaly and hepatomegaly may be evident on examination. Patients with advanced disease may experience pancytopenia leading to symptomatic anemia, easy bruising/bleeding, or recurrent infections.
Diagnostic Testing
In addition to routine labs, bone marrow assessment with flow cytometry, cytogenetics, FISH, and molecular testing/sequencing may be obtained.
TREATMENT
The decision to treat is based on the development of cytopenias, symptomatic splenomegaly, constitutional symptoms, and recurrent infections. The treatment options include cladribine and pentostatin. The addition of rituximab may deepen responses and lengthens remission but is also associated with increased immunosuppression.