Other leukaemias

Other leukaemias

Hairy cell leukaemia

Hairy cell leukaemia (HCL) is a rare chronic B-cell leukaemia characterised by distinctive biological features and unusual sensitivity to treatment. The name of the disease is a reference to the distinctive appearance of the malignant cell (Figs 24.1 and 24.2).

Fig 24.1 Normal lymphocyte and hairy cell.

Fig 24.2 Hairy cells seen with electron microscopy.

Clinical features

Patients often have non-specific symptoms including fatigue and weight loss. Infection, the main cause of morbidity and mortality, and bleeding are other possible presentations. The spleen is the probable site of origin of the malignant clone and splenomegaly is found in over 80% of cases. This may be massive and is usually not accompanied by lymphadenopathy. The liver is enlarged in 50% of patients.

Diagnosis

Most cases of HCL have a pancytopenia and there may be circulating hairy cells in the blood film. Neutropenia and monocytopenia are often particularly marked, accounting for the frequency of infection. Hairy cells strongly express the markers of mature activated B-cells: CD19, CD11c, CD20, CD22 and CD25 and CD103. The bone marrow is normally difficult to aspirate because of increased fibrosis; the trephine will show a variable number of infiltrating hairy cells. Where splenectomy is performed, the sinuses and cords are seen to be infiltrated by a uniform population of lymphoid cells with blood-filled spaces lined by hairy cells (the pathognomonic ‘pseudosinuses’ of HCL). There is no specific karyotypic abnormality.

Management

A minority of patients (perhaps 10%) are asymptomatic and in the first instance may require no intervention. Treatment options are as follows.

Nucleoside analogues

Purine analogues are highly effective treatment, producing a more complete and durable response than other therapies (Fig 24.3). Both cladribine and pentostatin give excellent long-term survivals (90–95% at 10 years) and death from HCL is rare.

Fig 24.3 Response of hairy cell leukaemia to treatment with cladribine (2-CDA).
Bone marrow examinations 1 and 2 showed numerous hairy cells, and bone marrow 3 a remission.

Interferon alfa

Although less effective than nucleosides, interferon alfa may still be used in patients with severe cytopenia or where the myelosuppressive effects of nucleosides are unacceptable. In the latter patients, G-CSF may also be helpful.

Major side-effects of interferon alfa include systemic symptoms such as pyrexia, lethargy and depression. Following cessation, the disease normally slowly relapses but it will often respond to reintroduction of the drug.

Splenectomy

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Tags: Haematology An Illustrated Colour Text

Jun 12, 2016 | Posted by admin in HEMATOLOGY | Comments Off

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