Intravascular large B-cell lymphoma
Synonyms and keywords: Intravascular lymphomatosis, angiotropic large cell lymphoma, angio-endotheliotropic (intravascular) lymphoma, angioendotheliomatosis proliferans systematisata, malignant angioendotheliomatosis

# Overview
Intravascular large B-cell lymphoma is a very rare subtype of diffuse large B-cell lymphoma (DLBCL). It is also considered a distinct type of non-Hodgkin lymphoma (NHL) in the World Health Organization (WHO) classification system. Intravascular large B-cell lymphoma affects small blood vessels.  It is a rare and aggressive variant of intravascular proliferation of clonal lymphocytes with little to no parenchymal involvement. Based on the clinical presentation, intravascular large B-cell lymphoma may be classified into either Western variant or Asian variant. On microscopic histopathological analysis, diffuse infiltrate of large atypical cells with irregular nuclear contours, vesicular chromatin, and occasional prominent nucleoli  are characteristic findings of intravascular large b-cell lymphoma. The incidence of intravascular large B-cell lymphoma increases with age; the median age at diagnosis is 67 years. Intravascular large B-cell lymphoma affects men and women equally. People with this type of lymphoma often have a poor prognosis. Symptoms of the intravascular large B-cell lymphoma include fever, weight loss, night sweats, chest pain, abdominal pain, bone pain, and painless swellings in the neck, axilla, groin, thorax, and abdomen. Lymph node biopsy is diagnostic of intravascular large B-cell lymphoma. CT, MRI, and PET scan may be helpful in the diagnosis of intravascular large B-cell lymphoma. The predominant therapy for intravascular large B-cell lymphoma  is chemotherapy. Adjunctive radiotherapy may be required.

# Classification
Based on the clinical presentation, intravascular large B-cell lymphoma may be classified into either Western variant or Asian variant.

# Pathophysiology
Intravascular large B-cell lymphoma  is characterized by a massive intravascular proliferation of atypical mononuclear cells which lodged in the lumina of small or intermediate vessels in many organs. The neoplastic lymphoid cells are large with prominent nucleoli and frequent mitotic figures. Fibrin thrombi, haemorrhage and necrosis may be seen.

## Microscopic Pathology
On microscopic histopathological analysis, diffuse infiltrate of large atypical cells with irregular nuclear contours, vesicular chromatin, and occasional prominent nucleoli  are characteristic findings of intravascular large b-cell lymphoma.

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

# Differentiating Intravascular Large B-Cell Lymphoma from other Diseases
Intravascular large B-cell lymphoma must be differentiated from other lymphomas with the help of clincal, morphological, immunophenotypic and genetic data as the treatment of all these conditions are different from each other.

# Epidemiology and Demographics

## Age
The incidence of intravascular large B-cell lymphoma increases with age; the median age at diagnosis is 67 years.

## Gender
Intravascular large B-cell lymphoma affects men and women equally.

# Risk Factors
There are no established risk factors for intravascular large B-cell lymphoma.

# Natural History, Complications and Prognosis
- Intravascular large B-cell lymphoma usually affects the small blood vessels in many organs, including: central nervous system, kidneys, lungs, and skin. However, almost any site can be affected.
- People with intravascular large B-cell lymphoma have a variety of symptoms. The symptoms will depend on the tissue or organ affected when the blood vessels become occluded. This type of lymphoma is often difficult to diagnose because the symptoms can be so varied.
- Intravascular large B-cell lymphoma is a fast-growing (aggressive) lymphoma.
- People with this type of lymphoma often have a poor prognosis.
- People with this type of lymphoma can also develop a very serious condition where certain parts of the immune system are activated (hemophagocytic syndrome).
- Hemophagocytic syndrome causes:
- Fever
- Enlarged liver and spleen (hepatosplenomegaly)
- A lower number of red blood cells, white blood cells and platelets in the blood (pancytopenia)

# Diagnosis

## Staging
Staging for Intravascular large B-cell lymphoma is provided in the following table:

## Symptoms
People with intravascular large B-cell lymphoma have a variety of symptoms. The symptoms will depend on the tissue or organ affected when the blood vessels become occluded. This type of lymphoma is often difficult to diagnose because the symptoms can be so varied. 
Most common symptoms of the intravascular large B-cell lymphoma include:
- Fever
- Weight loss
- Night sweats
- Painless swellings in the neck, axilla, groin, thorax, and abdomen
- Pain in the chest, abdomen, or bones

## Physical Examination

### Vitals
- Fever is often present

### Skin
- Skin rash

### HEENT
- Cervical lymphadenopathy

### Thorax
- Thoracic masses suggestive of central lymphadenopathy

### Abdomen
- Abdominal masses suggestive of central lymphadenopathy
- Hepatosplenomegaly

### Extremities
- Peripheral lymphadenopathy

## Laboratory Findings
Laboratory tests for intravascular large B-cell lymphoma include:
- Complete blood count (CBC): pancytopenia
- Blood chemistry studies:
- Cytogenetic analysis
- Flow cytometry
- Immunohistochemistry
- Immunophenotyping

### Biopsy
Lymph node biopsy is diagnostic of intravascular large B-cell lymphoma.

### Other Imaging Findings
CT, MRI, and PET scan may be helpful in the diagnosis of intravascular large B-cell lymphoma.

# Treatment

## Medical Therapy