A 56-year-old man presented with dysuria and during the investigation had a full blood count that was abnormal. The dysuria settled spontaneously. He was otherwise well with no symptoms and no weight loss, lethargy or sweats. He had no previous medical history of note. He was on no drugs. He had two brothers who were both well and a sister who was diagnosed with chronic lymphocytic leukaemia (CLL) at the age of 52 years. Clinical examination was entirely normal with, specifically, no palpable lymph nodes, liver or spleen. At presentation his white cell count was 14.3 × 109/l, neutrophils 2.4 × 109/l, lymphocytes 8 × 109/l, haemoglobin 15.1 g/dl and platelets 339 × 109/l.
What is the most likely cause of his lymphocytosis?
What investigations would you perform?
Could there be a link between his disease and his sister's CLL?
How would you manage his case?
The differential diagnosis for this patient’s lymphocytosis lies between a reactive process, which seems unlikely as he is obviously well, or a chronic lymphoproliferative disorder, such as CLL.1 A blood film was examined which revealed a large number of small, mature lymphocytes and frequent smear cells but was otherwise normal. Immunophenotyping performed by flow cytometry on his peripheral blood revealed that the majority of his lymphocytes were monoclonal with the following immunophenotype: CD19+, CD5+, CD23+, CD20weak, CD38+, surface immunoglobulin κweak. Therefore a diagnosis of CLL was established and he has early stage disease (Binet’s stage A; Table 19.1).2 The main differential diagnosis is another chronic lymphoproliferative disorder, such as mantle cell lymphoma or marginal zone lymphoma.
Table 19.1Binet staging system ||Download (.pdf) Table 19.1 Binet staging system
|Stage ||Organ enlargement* ||Haemoglobin (g/dl)** || ||Platelets (× 109/l) |
|A ||0, 1 or 2 areas ||≥10 ||AND ||≥100 |
|B ||3, 4 or 5 areas ||≥10 ||AND ||≥100 |
|C ||Not considered ||<10 ||OR ||<100 |
In CLL there is a familial risk, with approximately 3% of patients having a first-degree family member with CLL and a small number of families with several members suffering from CLL. In fact even in apparently ‘normal’ members (those with no clinical or blood-count evidence of CLL) of families with CLL there is a very high incidence of ‘subclinical’ CLL indicating a clear increase in risk.3 Familial CLL is not directly inherited and it appears that individuals probably inherit a predisposition to develop CLL, although no specific gene has been identified to date. Several genes have been ...