Diffuse Large B-cell Lymphoma

The Concept of the Disease

This is a generic terms for a clinical aggressive tumour of B-cells that does not fall into one the definitive disease categories such as Burkitt Lymphoma or Mediastinal B-cell Lymphoma. This is recognised to be a highly heterogeneous group.

How is it Diagnosed?

Lymph Node or other tissue biopsy

  • DLBCL consists of a population of highly proliferative large lymphoid cells which invade and destroy the normal structure of the lymph node or other tissues. About a third of cases present in sites other than a lymph node.
  • Almost all cases have an abnormal immunophenotype by flow cytometry and immunocytochemistry.
  • Monoclonality is demonstrated by antibody or PCR based techniques.
  • Translocations involving MYC, BCL2 and BCL6 are commonly demonstrated using FISH. Abnormalities of a wide range of genes, particularly those involving the NFkB pathway are described.
Lymph Node Morphology

Bone Marrow Trephine Morphology

Immunocytochemistry
K67 Staining
CD20 Staining
FISH – BCL2 Amplification

What is the Clinical Outcome?

50% of patients treated with R-CHOP chemotherapy are ultimately cured of their disease. However, this masks considerable heterogeneity of outcome.

The International prognostic index (IPI) is the standard method of assessing prognosis at presentation.

Score IPI Risk Group
0 – 1 Low
2 Low-intermediate
3 High-intermediate
4 High
Risk Factor Score +0 Score +1
Age (years) ≤60 >60
Stage (Ann Arbor) I or II II or IV
Number of extranodal sites 0 or 1 >1
Performance Status (ECOG) 0 or 1 >1
Serum LDH Normal Raised

Genetic abnormalities such as translocations involving MYC and the sub-classification of the tumour in germinal centre and activated B-cell types using gene expression profiling are also important determinants of outcome.