Angioimmunoblastic T-cell lymphoma overview

# Overview
Angioimmunoblastic T-cell lymphoma (AILT) is a mature T-cell lymphoma characterized by a polymorphous lymph node infiltrate showing a marked increase in follicular dendritic cells (FDCs) and high endothelial venules (HEVs). It is also known as immunoblastic lymphadenopathy (Lukes-Collins Classification) and AILD-type (lymphogranulomatosis X) T-cell lymphoma (Kiel Classification). Clonal T-cell receptor and immunoglobulin gene rearrangements are involved in the pathogenesis of angioimmunoblastic T-cell lymphoma. On gross pathology, aborization and proliferation of high endothelial venules are characteristic findings of angioimmunoblastic T-cell lymphoma.  On microscopic histopathological analysis, CD4+ T-cells, CD8+ T-cells, and polyclonal plasma cells are characteristic findings of angioimmunoblastic T-cell lymphoma. There are no established causes for angioimmunoblastic T-cell lymphoma. Angioimmunoblastic T-cell lymphoma must be differentiated from other diseases such as peripheral T-cell lymphoma-not otherwise specified, classical Hodgkin's lymphoma, diffuse large B cell lymphoma, and nodal marginal zone lymphoma. Angioimmunoblastic T-cell lymphoma commonly affects middle-aged or elderly individuals. Angioimmunoblastic T-cell lymphoma affects men and women equally. There are no established risk factors for angioimmunoblastic T-cell lymphoma. According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for angioimmunoblastic T-cell lymphoma. Common complications of angioimmunoblastic T-cell lymphoma include rheumatoid arthritis, autoimmune hemolytic anemia, vasculitis, and autoimmune thyroid disease. According to the Lugano classification, there are four stages of angioimmunoblastic T-cell lymphoma based on the number of nodes and extranodal involvement. The most common symptoms of angioimmunoblastic T-cell lymphoma include fever, weight loss, skin rash, night sweats,  edema, chest pain, abdominal pain, bone pain, fatigue, dark urine, shortness of breath, chronic pain, swelling of joints, and painless swelling of the neck, axilla, groin, thorax, and abdomen. Common physical examination findings of angioimmunoblastic T-cell lymphoma include fever, rash, ulcer, splenomegaly, hepatomegaly, pleural effusion, ascites, chest tenderness, abdomen tenderness, bone tenderness, arthritis, peripheral lymphadenopathy, and central lymphadenopathy. Laboratory tests for angioimmunoblastic T-cell lymphoma include complete blood count (CBC), polyclonal hypergammaglobulinemia, FISH, blood chemistry studies, flow cytometry, immunohistochemistry, and immunophenotyping. Abdominal CT scan may be helpful in the diagnosis of angioimmunoblastic T-cell lymphoma. Findings on CT scan suggestive of angioimmunoblastic T-cell lymphoma include mediastinal lymphadenopathy, inguinal lymphadenopathy, aortal lymphadenopathy, and bilaterally enlarged kidneys. MRI may be helpful in the diagnosis of angioimmunoblastic T-cell lymphoma. Lymph node or extranodal tissue biopsy is diagnostic of angioimmunoblastic T-cell lymphoma. Abdominal ultrasound may be helpful in the diagnosis of angioimmunoblastic T-cell lymphoma. Findings on ultrasound of the abdomen suggestive of angioimmunoblastic T-cell lymphoma include hepatomegaly and splenomegaly. Positron emission tomographic scan may be helpful in the diagnosis of angioimmunoblastic T-cell lymphoma. Findings on positron emission tomographic scan suggestive of angioimmunoblastic T-cell lymphoma include lymphadenopathy and bilaterally enlarged kidneys. Other diagnostic studies for angioimmunoblastic T-cell lymphoma include laparoscopy, laparotomy, bone marrow aspiration, and bone marrow biopsy. The predominant therapy for angioimmunoblastic T-cell lymphoma is chemotherapy. Adjunctive stem cell transplantation may be required in certain cases.

# Pathophysiology
Clonal T-cell receptor and immunoglobulin gene rearrangements are involved in the pathogenesis of angioimmunoblastic T-cell lymphoma. On gross pathology, aborization and proliferation of high endothelial venules are characteristic findings of angioimmunoblastic T-cell lymphoma. On microscopic histopathological analysis, CD4+ T-cells, CD8+ T-cells, and polyclonal plasma cells are characteristic findings of angioimmunoblastic T-cell lymphoma.

# Causes
There are no established causes for angioimmunoblastic T-cell lymphoma.

# Differential Diagnosis
Angioimmunoblastic T-cell lymphoma must be differentiated from other diseases such as peripheral T-cell lymphoma-not otherwise specified, classical Hodgkin's lymphoma, diffuse large B cell lymphoma, and nodal marginal zone lymphoma.

# Epidemiology and demographics
Angioimmunoblastic T-cell lymphoma commonly affects middle-aged or elderly patients. Angioimmunoblastic T-cell lymphoma affects males and females equally.

# Risk Factors
There are no established risk factors for angioimmunoblastic T-cell lymphoma.

# Screening
According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for angioimmunoblastic T-cell lymphoma.

# Complications
Common complications of angioimmunoblastic T-cell lymphoma include rheumatoid arthritis, autoimmune hemolytic anemia, vasculitis, and autoimmune thyroid disease.

# Diagnosis

## Staging
According to the Lugano classification, there are four stages of angioimmunoblastic T-cell lymphoma based on the number of nodes and extranodal involvement.

## Symptoms
The most common symptoms of angioimmunoblastic T-cell lymphoma include fever, weight loss, skin rash, night sweats,  edema, chest pain, abdominal pain, bone pain, fatigue, dark urine, shortness of breath, chronic pain, swelling of joints, and painless swelling of the neck, axilla, groin, thorax, and abdomen.

## Physical Examination
Common physical examination findings of angioimmunoblastic T-cell lymphoma include fever, rash, ulcer, splenomegaly, hepatomegaly, pleural effusion, ascites, chest tenderness, abdomen tenderness, bone tenderness, peripheral lymphadenopathy, and central lymphadenopathy.

## Laboratory Tests
Laboratory tests for angioimmunoblastic T-cell lymphoma include complete blood count (CBC), polyclonal hypergammaglobulinemia, FISH, blood chemistry studies, flow cytometry, immunohistochemistry, and immunophenotyping.

## CT
Abdominal CT scan may be helpful in the diagnosis of angioimmunoblastic T-cell lymphoma. Findings on CT scan suggestive of angioimmunoblastic T-cell lymphoma include mediastinal lymphadenopathy, inguinal lymphadenopathy, aortal lymphadenopathy, and bilaterally enlarged kidneys.

## MRI
MRI may be helpful in the diagnosis of angioimmunoblastic T-cell lymphoma.

## Biopsy
Lymph node or extranodal tissue biopsy is diagnostic of angioimmunoblastic T-cell lymphoma.

## Ultrasound
Abdominal ultrasound may be helpful in the diagnosis of angioimmunoblastic T-cell lymphoma. Findings on ultrasound of the abdomen suggestive of angioimmunoblastic T-cell lymphoma include hepatomegaly and splenomegaly.

## Other Imaging Studies
Positron emission tomographic scan may be helpful in the diagnosis of angioimmunoblastic T-cell lymphoma. Findings on positron emission tomographic scan suggestive of angioimmunoblastic T-cell lymphoma include lymphadenopathy and bilaterally enlarged kidneys.

## Other Diagnostic Studies
Other diagnostic studies for angioimmunoblastic T-cell lymphoma include laparoscopy, laparotomy, bone marrow aspiration, and bone marrow biopsy.

# Treatment

## Medical Therapy
The predominant therapy for angioimmunoblastic T-cell lymphoma is chemotherapy. Adjunctive stem cell transplantation may be required.