Low-grade B-cell lymphoma (because of the build up of the B cells in the lymph nodes over time) with lymphocytic leucocytosis

Demographics: M:F 2:1, peak 60-80 years. Most common leukaemia

Risk factors: increasing age, family history, organic solvent exposure (agent orange)

Aetiology:

• Unknown genetic mutations that cause interferes with the B cell receptors
• There are mutations that are associated with CLL such as del(17p13) → results in the deactivation of the p53 tumour suppressor protein → results in poor prognosis

Pathophysiology:

• Genetic mutations → increased proliferation, impaired maturation, differentiation (decreased function) and apoptosis of B cells (live forever) in the bone marrow.
• Accumulate in bone marrow → other cells ‘crowded out’ → impairs the maturation and development of other cells in the bone marrow → anaemia (decrease RBCs), thrombocytopenia (decreased platelets), decreased granulocytes (such as neutrophils). The increased lymphocytes eventually spill into the circulation / organs (particularly lymph nodes, liver and spleen)
• cells can mature partly but still have impaired function.

Presentation: mostly asymptomatic, incidental diagnosis picked up on FBC

Clinical features:

• Weight loss, fever, night sweats, fatigue (B symptoms)