# B-cell lymphoma

The B-cell lymphomas are types of lymphoma affecting B cells. Lymphomas are "blood cancers" in the lymph nodes. They develop more frequently in older adults and in immunocompromised individuals.
B-cell lymphomas include both Hodgkin's lymphomas and most non-Hodgkin lymphomas. They are typically divided into low and high grade, typically corresponding to indolent (slow-growing) lymphomas and aggressive lymphomas, respectively. As a generalisation, indolent lymphomas respond to treatment and are kept under control (in remission) with long-term survival of many years, but are not cured. Aggressive lymphomas usually require intensive treatments, with some having a good prospect for a permanent cure.
Prognosis and treatment depends on the specific type of lymphoma as well as the stage and grade. Treatment includes radiation and chemotherapy. Early-stage indolent B-cell lymphomas can often be treated with radiation alone, with long-term non-recurrence. Early-stage aggressive disease is treated with chemotherapy and often radiation, with a 70–90% cure rate. Late-stage indolent lymphomas are sometimes left untreated and monitored until they progress. Late-stage aggressive disease is treated with chemotherapy, with cure rates of over 70%.

## Types

There are numerous kinds of lymphomas involving B cells. The most commonly used classification system is the WHO classification, a convergence of more than one, older classification systems.

### Common

Five account for nearly three out of four patients with non-Hodgkin lymphoma:
* Diffuse large B-cell lymphoma (DLBCL)
* Follicular lymphoma
* Marginal zone B-cell lymphoma (MZL) or mucosa-associated lymphatic tissue lymphoma (MALT)
* Small lymphocytic lymphoma (SLL, also known as chronic lymphocytic leukemia, CLL)
* Mantle cell lymphoma (MCL)

### Rare

The remaining forms are much less common:
* DLBCL variants or sub-types of
** Primary mediastinal B-cell lymphoma
** T cell/histiocyte-rich large B-cell lymphoma
** Primary cutaneous diffuse large B-cell lymphoma, leg type (Primary cutaneous DLBCL, leg type)
** EBV positive diffuse large B-cell lymphoma of the elderly
** Diffuse large B-cell lymphoma associated with chronic inflammation
** Fibrin-associated diffuse large B-cell lymphoma
** Primary testicular diffuse large B-cell lymphoma
* Burkitt's lymphoma
* Lymphoplasmacytic lymphoma, which may manifest as Waldenström's macroglobulinemia
* Nodal marginal zone B cell lymphoma (NMZL)
* Splenic marginal zone lymphoma (SMZL)
* Intravascular lymphomas variants
** Intravascular large B-cell lymphoma
** Intravascular NK-cell lymphoma
** Intravascular T-cell lymphoma
* Primary effusion lymphoma
* Lymphomatoid granulomatosis
* Primary central nervous system lymphoma
* ALK+ large B-cell lymphoma
* Plasmablastic lymphoma
* Large B-cell lymphoma arising in HHV8-associated multicentric Castleman's disease
* B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma
* B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma

### Other

Additionally, some researchers separate out lymphomas that appear to result from other immune system disorders, such as AIDS-related lymphoma.
Classic Hodgkin's lymphoma and nodular lymphocyte predominant Hodgkin's lymphoma are now considered forms of B-cell lymphoma.

## Diagnosis

When a person appears to have a B-cell lymphoma, the main components of a workup (for determining the appropriate therapy and the person's prognosis) are:
* Establishing the precise subtype: Initially, an incisional or excisional biopsy is preferred. A core needle biopsy is discouraged except in case a lymph node is not easily accessible. Fine-needle aspiration is only acceptable in selected circumstances, in combination with immunohistochemistry and flow cytometry.
* Determining the extent of the disease (localized or advanced; nodal or extranodal)
* The person's general health status.
Main immunohistochemistry markers in common types of B-cell lymphoma. :
| | Follicular lymphoma | Marginal zone B-cell lymphoma (MZL) or mucosa-associated lymphatic tissue (MALT) lymphoma | Small lymphocytic lymphoma (SLL) / chronic lymphocytic leukemia (CLL) | Mantle cell lymphoma (MCL) |
| CD5 | - | - | + | + |
| CD10 | + | - | - | - |
| CD23 | - | - | + | - |
| Cyclin D1 | - | - | - | + |

## Associated chromosomal translocations

Chromosomal translocations involving the immunoglobulin heavy locus is a classic cytogenetic abnormality for many B-cell lymphomas, including follicular lymphoma, mantle cell lymphoma and Burkitt's lymphoma. In these cases, the immunoglobulin heavy locus forms a fusion protein with another protein that has pro-proliferative or anti-apoptotic abilities. The enhancer element of the immunoglobulin heavy locus, which normally functions to make B cells produce massive production of antibodies, now induces massive transcription of the fusion protein, resulting in excessive pro-proliferative or anti-apoptotic effects on the B cells containing the fusion protein.
In Burkitt's lymphoma and mantle cell lymphoma, the other protein in the fusion is c-myc (on chromosome 8) and cyclin D1 (on chromosome 11), respectively, which gives the fusion protein pro-proliferative ability. In follicular lymphoma, the fused protein is Bcl-2 (on chromosome 18), which gives the fusion protein anti-apoptotic abilities.