Diffuse large B cell lymphoma overview

# Overview
Diffuse large B-cell lymphoma (DLBCL or DLBL) is a cancer of B cells, a type of white blood cell responsible for producing antibodies. Diffuse large B cell lymphoma may be classified based on location into nodal and extranodal disease and based on molecular, genetic, and immunohistochemical features into more than 20 subgroups. Diffuse large B cell lymphoma may be classified into 2 subtypes based on gene expression profiles. The progression to diffuse large B cell lymphoma involves the microRNAs (miRNAs). On microscopic histopathological analysis, diffuse large B cell lymphoma can be divided into three variants: centroblastic, immunoblastic, and anaplastic. There are no established causes for diffuse large B cell lymphoma. Diffuse large B cell lymphoma is the most common type of non-Hodgkin lymphoma among adults, with an annual incidence of 78 cases per 100,000 people per year. This cancer occurs primarily in older individuals, with a median age of diagnosis at approximately 70 years of age, though it can also occur in children and young adults in rare cases. The most potent risk factor in the development of diffuse large B cell lymphoma is immunodeficiency. Diffuse large B cell lymphoma must be differentiated from other diseases such as follicular lymphoma, Mucosa-Associated Lymphatic Tissue lymphoma(MALT), small cell lymphocytic lymphoma, and Mantle cell lymphoma (MCL). The prognosis of diffuse large B cell lymphoma depends on the stage of the disease. Diffuse large B cell lymphoma is associated with a 5 year survival rate ranging from 70% to more than 90% among children. According to the Lugano classification, there are four stages of diffuse large B cell lymphoma based on the number of nodes involved and extranodal status. The most common symptoms of diffuse large B cell lymphoma include a rapidly enlarging, non-painful mass that may be located in neck, groin or abdomen. The less common symptoms of diffuse large B cell lymphoma include fever, weight loss and drenching night sweats. Common physical examination findings of diffuse large B cell lymphoma include a non tender mass which can arise in virtually any part of the body. Laboratory tests of diffuse large B cell lymphoma include complete blood count, blood chemistry studies, flow cytometry, immunohistochemistry, cytology, genetic testing, and immunophenotyping. CT scan, MRI, and PET may be helpful in the diagnosis of diffuse large B cell lymphoma. Lymph node or extranodal tissue biopsy is diagnostic of large B cell lymphoma. Other diagnostic studies for diffuse large B cell lymphoma include laparoscopy, laparotomy, and bone marrow aspiration and biopsy. The optimal therapy for diffuse large B cell lymphoma depends on the stage at diagnosis. The predominant therapy for diffuse large B cell lymphoma is chemotherapy. Adjunctive radiotherapy may be required. Active areas of research include genetic studies to assess the genetic role in diffuse large B cell lymphoma and novel therapeutic regimens that evaluate the efficacy and safety of novel regimens in in newly diagnosed diffuse large B cell lymphoma.

# Classification
Diffuse large B cell lymphoma may be classified based on location into nodal and extranodal disease and based on molecular, genetic, and immunohistochemical features into more than 20 subgroups.

# Pathophysiology
Diffuse large B cell lymphoma is mainly caused by genetic mutations. Genetic expression of germinal centers B cell like are associated with favourable prognosis. Some studies have established an association between microRNA expression and B cell lymphoma pathogenesis. The studies showed poor prognosis of microRNA expressed lymphomas. MicroRNAs participate in development of B cell receptor signalling, B cell migration, and class switching of immunoglobulins. On microscopic pathology, diffuse large B cell lymphoma has three variant pictures which include centroblastic, immunoblastic, and anaplastic forms of DLBCL.

# Causes
There are no established causes for diffuse large B cell lymphoma.

# Differential diagnosis
Diffuse large B cell lymphoma must be differentiated from other diseases such as follicular lymphoma, Mucosa-Associated Lymphatic Tissue lymphoma(MALT), small cell lymphocytic lymphoma, and mantle cell lymphoma (MCL).

# Epidemiology and demographics
Diffuse large B cell lymphoma is the most common type of non-Hodgkin lymphoma among adults, with an annual incidence of 78 cases per 100,000 people per year. This cancer occurs primarily in older individuals, with a median age of diagnosis at approximately 70 years of age, though it can also occur in children and young adults in rare cases.

# Risk factors
According to the American Cancer Society, There are several Factors including Old Age, Male Gender, White Ethnicity, Geography, exposure to Certain Drugs and Chemicals, Radiation exposure, and weak Immune System that can increase the chances of getting Non Hodgkin Lymphoma(NHL) among which Diffuse Large B cell Lymphoma is the Most common sub-type. Some Other Risk Factors include hepatitis C virus (HCV) seropositivity, high body mass as a young adult, HIV, and Family History of Lymphoma

# Screening
Screening for diffuse large B cell lymphoma is not recommended.

# Prognosis
The prognosis of diffuse large B cell lymphoma depends on the stage of the disease. Diffuse large B cell lymphoma is associated with a 5 year survival rate ranging from 70% to more than 90% among children.

# Diagnosis

## Staging
According to the Lugano classification, there are four stages of diffuse large B cell lymphoma based on the number of nodes involved and extranodal status.

## History and symptoms
The most common symptoms of diffuse large B cell lymphoma include a rapidly enlarging, non-painful mass that may be located in neck, groin or abdomen. The less common symptoms of diffuse large B cell lymphoma include fever, weight loss and drenching night sweats.

## Physical examination
Common physical examination findings of diffuse large B cell lymphoma include a non tender mass which can arise in virtually any part of the body.

## Laboratory Findings
Laboratory tests of diffuse large B cell lymphoma include complete blood count, blood chemistry studies, flow cytometry, immunohistochemistry, cytology, genetic testing, and immunophenotyping.

## Electrocardiogram
There are no electrocardiogam findings associated with diffuse large B cell lymphoma.

## Chest X ray
There are no chest X ray findings associated with diffuse large B cell lymphoma.

## CT
CT scan may be helpful in the diagnosis of diffuse large B cell lymphoma. Fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) scan is now recommended as the gold standard for staging DLBCL patients

## MRI
For suspected lymphoma of the Nervous System, magnetic resonance imaging (MRI) is the modality of choice. Neck MRI is helpful in the diagnosis of diffuse large B cell lymphoma.

## Biopsy
Lymph node or extranodal tissue biopsy is diagnostic of large B cell lymphoma.

## Other Imaging Studies
PET scan may be helpful in the diagnosis of diffuse large B cell lymphoma.

## Other Diagnostic Studies
Other diagnostic studies for diffuse large B cell lymphoma include laparoscopy, laparotomy, and bone marrow aspiration and biopsy.

# Treatment

## Medical therapy
The optimal therapy for diffuse large B cell lymphoma depends on the stage at diagnosis. The predominant therapy for diffuse large B cell lymphoma is chemotherapy. Adjunctive radiotherapy may be required.

## Surgery
Surgical intervention is not recommended for the management of diffuse large B cell lymphoma.

## Primary prevention
There are no primary preventive measures for diffuse large B cell lymphoma.

## Secondary prevention
There are no secondary preventive measures for diffuse large B cell lymphoma.

## Future or Investigational therapies
Active areas of research include genetic studies to assess the genetic role in diffuse large B cell lymphoma and novel therapeutic regimens that evaluate the efficacy and safety of novel regimens in in newly diagnosed diffuse large B cell lymphoma.