Page 249 - Essential Haematology

Chapter 18 Chronic lymphoid leukaemias / 235

has a peak incidence between 60 and 80 years of
Table 18.1 Classifi cation of the chronic

lymphoid leukaemias. age. The aetiology is unknown but there are
geographical variations in incidence. It is the
B - cell T - cell most common of the leukaemias in the Western
world but rare in the Far East. In contrast to other
Chronic lymphocytic Large granular
forms of leukaemia there is no higher incidence
leukaemia (CLL) lymphocytic
after previous chemotherapy or radiotherapy.
Prolymphocytic leukaemia

There is a sevenfold increased risk of CLL in the
leukaemia (PLL) T - cell prolymphocytic
close relatives of patients which indicates a genetic
Hairy cell leukaemia leukaemia (T - PLL)
(HCL) Adult T - cell leukaemia/ predisposition.

Plasma cell leukaemia lymphoma The tumour cell appears to be a relatively
mature B cell with weak surface expression of
S é zary syndrome (see

Chapter 20 ) immunoglobulin (IgM or IgD). The cells accumu-
late in the blood, bone marrow, liver, spleen and
lymph nodes as a result of increased production
Source : WHO (2008) classifi cation (see p. 426 ) .

and prolonged lifespan with impaired apoptosis.
Small lymphocytic lymphoma (SLL) (see Chapter
20 ) is the tissue equivalent of CLL. Th e lymphoma
cells have the same immunophenotype and cytoge-
netics but in SLL there is solid tissue disease and
Several disorders are included in this group charac- fewer than 5 × 10 /L circulating monoclonal B
9
terized by accumulation in the blood of mature cells.
lymphocytes of either B - or T - cell type (Table 18.1 ). Monoclonal B - cell lymphocytosis Clonal B

There is some overlap with the non - Hodgkin lym- cells with the same phenotype as CLL are found at
phomas. In many cases of non - Hodgkin lymphoma, low levels in the blood of many older patients.
lymphoma cells are found in the blood and the Indeed, this monoclonal B - cell lymphocytosis
distinction between chronic leukaemia and lym- (MBL) has been demonstrated in 3% of patients
phoma is arbitrary, depending on the relative pro- over the age of 50 years and it is believed that all
portion of the disease in soft tissue masses compared cases of clinical CLL progress from this state. Similar
to blood and bone marrow. In general, the diseases genetic changes to these found in CLL may be
are incurable but tend to run a chronic and fl uctuat- present. If CLL is to be diagnosed there must be a
ing course. monoclonal B - cell count of > 5 × 10 /L or tissue
9
involvement outside the bone marrow.
Diagnosis
Clinical f eatures

This group is characterized by a chronic persistent
lymphocytosis. Subtypes are distinguished by 1 The disease occurs in older subjects with

morphology, immunophenotype and cytogenetics. only 15% of cases before 50 years of age. Th e
DNA analysis may be useful in showing a mono- male : female ratio is 2 : 1.
clonal rearrangement of either immunoglobulin or 2 Most cases are diagnosed when a routine blood

T - cell receptor genes. test is performed. With increasing routine
medical check - ups, this proportion is rising to
B - C ELL D ISEASES > 80%.

3 Symmetrical enlargement of cervical, axillary or

inguinal lymph nodes is the most frequent clini-
Chronic l ymphocytic l eukaemia

cal sign (Fig. 18.1 ). The nodes are usually discrete
Chronic lymphocytic leukaemia (CLL) is the most and non - tender. Tonsillar enlargement may be a
common of the chronic lymphoid leukaemias and feature.