Hairy cell leukemia

Hairy cell leukemia is a rare and indolent form of small mature B-cell leukaemias.

Epidemiology

Its annual incidence is estimated at around 0.3 cases per 100 000, and the disease comprises 2-3% of all leukaemias. There is a recognized male predilection of around 4:1 with a median age of around 55 years.

Pathology

It can present with splenomegaly, vulnerability to recurrent infections, pancytopenia and bone marrow involvement with fibrosis.

Skeletal lesions uncommonly occur (~3% of cases) and when they do are commonly lytic with the most common sites of involvement being the femoral head and neck ⁵. Skeletal involvement is typically associated with high tumor burden and bone marrow infiltration.

Subtypes

Two main subtypes have been described

• classical hairy cell leukemia: 90%
• hairy cell leukemia variant (HCL-V): 10%

Treatment and prognosis

The combination of cladribine and pentostatin, either single or combined, with an anti-CD20 monoclonal antibody achieved stable results ⁷.

See also

• WHO classification of tumors of hematopoietic and lymphoid tissues