Hairy cell leukaemia

Hairy cell leukaemia (HCL) is an uncommon, indolent, mature B-cell neoplasm. It is characterised by symptoms of fatigue, a markedly enlarged spleen, pancytopenia, and a distinctive histological appearance on peripheral blood smear and bone marrow biopsy.

HCL is not curable. However, it is highly responsive to therapy; median relapse-free survival of a decade or more has been reported.

In asymptomatic patients with well-preserved blood counts, immediate treatment is not required.

In symptomatic patients or those with worsening blood counts, treatment with purine analogues is recommended.

Supportive care with antibiotics, anti-infective prophylaxis, granulocyte colony-stimulating factor, and irradiated blood products may be required as part of treatment.

HCL is an indolent mature B-cell neoplasm. It is considered to be a type of non-Hodgkin's lymphoma. Seen under the microscope, the leukaemic cells have delicate cytoplasmic projections resembling hair (‘hairy cells’). HCL has a characteristic presentation of pancytopenia, splenomegaly, and hairy cells in the peripheral blood, bone marrow, and other haematopoietic organs.[Figure caption and citation for the preceding image starts]: Cytospin prepared from bone marrow aspirate illustrates the typical cell cytology, with oval- to bean-shaped nuclei and moderate amounts of cytoplasm with irregular cytoplasmic borders (Wright Giemsa 100x oil)From the collection of Lynn Moscinski, MD [Citation ends].[Figure caption and citation for the preceding image starts]: Sections of core biopsy demonstrate lymphocytes with obvious cytoplasm within the marrow interstitium, associated with dilatation of marrow sinuses and red blood cell collections (H&E 50x oil)From the collection of Lynn Moscinski, MD [Citation ends].