by Jason Wasserman MD PhD FRCPC and Phil Berardi MD PhD FRCPC
November 14, 2023

Aggressive B cell lymphoma is a term used to describe a group of immune system cancers made up of cells called B cells. Although this is considered enough to establish a formal diagnosis, additional tests might be needed to refine how best to group or subclassify the disease.

What types of B cell lymphoma are included in this group?

There are many different types of aggressive B cell lymphomas. The more common subtypes include:

What is the most common type of aggressive B cell lymphoma?

Diffuse large B cell lymphoma (DLBCL) is the most common type of aggressive B cell lymphoma.

Why are these cancers described as aggressive?

Aggressive B cell lymphomas are made up of tumour cells that divide (create new tumour cells) much faster than other more indolent (slower growing) types of B cell lymphoma. These lymphomas also tend to spread quickly to other parts of the body.

How is this diagnosis made?

The diagnosis can only be made when a sample of the tumour is removed and the tissue is examined under a microscope by a pathologist.

What does an aggressive B cell lymphoma look like under the microscope?

Because the term aggressive B cell lymphoma describes a group of cancers, the microscopic appearance of the tumour can vary somewhat based on the specific type of cancer present. However, most cancers in this group are made up of medium to large-sized lymphocytes arranged in nests or sheets. The cytoplasm (body of the cell) may appear eosinophilic (pink) or clear and the nucleus (the part of the cell that holds the genetic material) is usually enlarged, and round, and clumps of genetic material called nucleoli are often seen. Mitotic figures (cells dividing to create new cells) and necrosis (dead cells) are common.

This picture shows a tumour that was initially diagnosed as an aggressive B cell lymphoma. The final diagnosis was diffuse large B cell lymphoma.

What other tests may be performed to confirm the diagnosis?

When evaluating a potential aggressive B cell lymphoma, a variety of tests including immunohistochemistry (IHC), flow cytometry, fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR), and next-generation sequencing (NSG) may be performed to confirm the diagnosis. These tests allow pathologists to determine the types of cells present in the tumour and to look for molecular changes to will help them narrow down the diagnosis to a more specific type of lymphoma.

Given that the cancers in this group arise from B cells, the tumour cells generally show strong expression of B cell markers including CD19, CD20, CD22, CD79a and PAX5 and the immune cell marker CD45. Other markers commonly expressed by cancers in this group include CD10, BCL6, BCL2, MUM1 and c-MYC. The Ki67 labelling index (a measure of how quickly the abnormal cells are dividing) is usually elevated to a level >20%. Some of these cancers can also be associated with an underlying Epstein-Barr virus (EBV) infection. In this situation, tests such as in situ hybridization (ISH) for EBER may also be performed.

Diffuse large B cell lymphoma (DLBCL)

Burkitt lymphoma

EBV-positive diffuse large B cell lymphoma

Plasmablastic lymphoma

Other helpful resources

American Cancer Society

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Aggressive B cell lymphoma