Hairy-cell leukaemia (HCL) is an established clinicopathological entity typified by a chronic picture of substantial splenomegaly, less frequent hepatomegaly, and only inconspicuous lymphadenopathy. Central to the diagnosis is the pathognomonic hairy cell (HC), a dis tinctive mononuclear cell that circulates in varying numbers and infiltrates a variety of organs, including the bone marrow and spleen. Peripheral pancytopenia is often present, and circulating HCs may be infrequent. HCs are invariably present in the bone marrow; but, per haps because of the extensive fibrosis characteristic of the disease, the marrow is frequently difficult to aspirate, and confirmation of the diagnosis may require histopathological ex amination of biopsy material. The incidence of the disease has been given as 2% ofleukaemias [29, 319] or as approximately 1 % of identifiable lymphomas [230]. Our own experience of collecting cases in the United Kingdom leads us to expect that at any given time one patient with HCL will be attending a clinic serving some 150,000 people.

Inhalt
1 Introduction.- 2 Clinical Aspects.- 2.1 Occurrence.- 2.2 Clinical Features at Presentation.- 2.3 Haematology at Presentation.- 2.4 Other Investigations.- 2.5 Treatment.- 2.6 Clinical and Haematological Progress.- 2.7 Complications and Cause of Death.- 3 Pathology.- 3.1 Bone Marrow.- 3.2 Spleen.- 3.3 Liver.- 3.4 Lymph Nodes.- 4 The Hairy Cell: Cytological Aspects.- 4.1 Cytology.- 4.2 Cytochemistry.- 4.3 Ultrastructure.- 4.4 Cytokinetics.- 4.5 Cytogenetics.- 4.6 Metabolism.- 4.7 Culture.- 5 The Hairy Cell: Immunological Aspects.- 5.1 Transformation and Cytotoxicity Studies.- 5.2 Surface Receptors.- 5.3 Monocytic Features.- 5.4 Immunoglobulin Synthesis and Secretion.- 5.5 Summary of the Immunological Membrane Phenotype of Typical HCs.- 5.6 T-cell Features.- 6 Other Haemic Cells.- 6.1 Granulocytes.- 6.2 Monocytes.- 6.3 Platelets.- 6.4 Lymphocytes.- 7 Diagnosis.- 7.1 Differential Diagnosis.- 7.2 A New Distinct Entity.- 8 Conclusions and Future Trends.- 9 References.- 10 Subject Index.