Enteropathy-associated T-cell lymphoma overview
Synonyms and keywords: Enteropathy-type T-cell lymphoma; Intestinal T-cell lymphoma; EATL; ETTL

# Overview
Enteropathy-associated T-cell Lymphoma (EATL), also enteropathy-type T-cell lymphoma (ETTL), is a type of T-cell non-hodgkin lymphoma that affects the small intestine, it is composed of large lymphoid cells. Enteropathy-associated T-cell lymphoma has two subtypes, type I enteropathy-associated T-cell lymphoma which has a strong association with celiac disease and it is more common in western countries and type II enteropathy-associated T-cell lymphoma which is mostly found among the Asian population. Genes involved in the pathogenesis of this disease include 8q24, T-cell receptor (TCR) beta and gamma, and 16q genes. On gross pathology, multiple intestinal ulcers are characteristic findings of EATL. On microscopic histopathological analysis, monotonous cells, round or angulated vesicular nuclei, and prominent nucleoli are characteristic findings of enteropathy-associated T-cell lymphoma. There are no established causes for enteropathy-associated T-cell lymphoma. EATL must be differentiated from other diseases such as peptic ulcer, poorly-differentiated adenocarcinoma, MALT lymphoma, diffuse large B cell lymphoma, and mantle cell lymphoma. The incidence of enteropathy-associated T-cell lymphoma is very low worldwide. There are no established risk factors for enteropathy-associated T-cell lymphoma.  Common complications of enteropathy-associated T-cell lymphoma include ulcer, obstruction, and perforation of small intestine. Prognosis is generally poor. According to the Lugano classification, there are four stages of enteropathy-associated T-cell lymphoma based on the number of nodes and extranodal involvement. The most common symptoms of enteropathy-associated T-cell lymphoma include fever, weight loss, skin rash, night sweats, chest pain, abdominal pain, bone pain, and painless swelling in the neck, axilla, groin, thorax, and abdomen. Common physical examination findings of enteropathy-associated T-cell lymphoma  include fever, rash, ulcer, chest tenderness, abdomen tenderness, bone tenderness, peripheral lymphadenopathy. Lymph node or endoscopic tissue biopsy is diagnostic of enteropathy-associated T-cell lymphoma. CT scan may be helpful in the diagnosis of enteropathy-associated T-cell lymphoma. Findings on CT scan suggestive of enteropathy-associated T-cell lymphoma include bowel wall thickening, mesenteric fat infiltration, mesentric lymph node cavitation, intussusception, and small-sized spleen. Other diagnostic studies for enteropathy-associated T-cell lymphoma include bone marrow aspiration and bone marrow biopsy. There is no treatment, the mainstay of therapy is supportive care. The optimal therapy depends on the extent and the location of the lymphoma in the small intestine.  Surgery is not the first line treatment option for patients with enteropathy-associated T-cell lymphoma. Local debulking is usually reserved for patients with tumor masses with a high risk of obstruction, hemorrhage, and perforation

# Historical Perspective
The association between celiac disease and enteropathy-associated T cell lymphoma was made during 2008 by World Health Organization.

# Classification
Enteropathy-associated T-cell lymphoma may be classified according to World Health Organization (WHO) into 2 subtypes: Type I enteropathy-associated T-cell lymphoma, type II enteropathy-associated T-cell lymphoma.

# Pathophysiology
Enteropathy-associated T-cell Lymphoma (EATL), also enteropathy-type T-cell lymphoma (ETTL), is a type of T-cell lymphoma that affects the small intestine. Frequent activating mutations in the JAK-STAT pathway in EATL suggests that deregulation of cytokine signaling is the early event in lymphomagenesis. Intraepithelial T cells are presumed to be the cell of origin of EATL (and RCD II). Variable degrees of transformations can be seen on histopathology of this tumor, but usually presents as large lymphoid cells. These cancerous T-cells are a possible consequence of either refractory cases of celiac disease or chronic untreated celiac disease patients. Most commonly occurs in the jejunum or ileum. SETD2 was found to be the most often silenced gene in EATL according to studies. The JAK-STAT pathway is the most frequently mutated pathway. Mutations in KRAS, TP53, and TERT Type I EATL and type II EATL (monomorphic intestinal T cell lymphoma) identified as well which have overlapping genetic alterations.

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

# Differentiating Enteropathy-associated T cell lymphoma from Other Diseases
Enteropathy-associated T-cell lymphoma must be differentiated from other diseases such as: Peptic ulcer, poorly-differentiated adenocarcinoma, MALT lymphoma, Diffuse large B cell lymphoma (DLBCL), and Mantle cell lymphoma.

# Epidemiology and Demographics
Enteropathy-associated T cell lymphoma is a very rare form of extranodal non-Hodgkin lymphoma, with an average incidence of 0.10 to 1.5 per 100,000 inhabitants per year, mostly occurs in the older adult, peak incidence average of 59 years old and involves proximal small intestine (duodenum and jejunum). Type II EATL is more common in the Asian population and not related to celiac disease, whereas type I EATL is more frequently happens in western Europe.

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

# Screening
There is insufficient evidence to recommend routine screening for enteropathy-associated T-cell lymphoma.

# Natural History, Complications, and Prognosis
Enteropathy-associated T-cell lymphoma is usually a fast-growing (aggressive) lymphoma. It is associated with celiac disease (sprue). Most adults are diagnosed with celiac disease at the same time as their lymphoma or shortly before their lymphoma is diagnosed. Enteropathy-associated T-cell lymphoma may spread to the liver, spleen, lymph nodes, gallbladder, stomach, colon or skin.

# Diagnosis

## Diagnostic Study of Choice
Endoscopic biopsy is the diagnostic study of choice for enteropathy-associated T cell lymphoma, though CT scan and other imaging studies can be helpful.

## History and Symptoms
Symptoms of the enteropathy-associated T-cell lymphoma include: Fever, Weight loss, Night sweats, Diarrhea, Skin rash, Chest pain, Abdominal pain, Bone pain, and painless swelling in the neck, axilla, groin, thorax, and abdomen.

## Physical Examination

## Vitals
- Fever is often present

## Skin
- Rash
- Ulcer

## HEENT
- Cervical lymphadenopathy

## Thorax
- Thoracic masses suggestive of central lymphadenopathy
- Chest tenderness

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

## Extremities
- Peripheral lymphadenopathy
- Bone tenderness

## Laboratory Findings
- Laboratory tests for enteropathy-associated T-cell lymphoma include:
Complete blood count (CBC)
Blood chemistry studies
Cytogenetic analysis
Flow cytometry
Immunohistochemistry
Immunophenotyping: CD3+, CD4-, CD5-, CD7+, CD30+, CD56+, CD103+, CD8+/-, and TCR beta+/-
- Complete blood count (CBC)
- Blood chemistry studies
- Cytogenetic analysis
- Flow cytometry
- Immunohistochemistry
- Immunophenotyping: CD3+, CD4-, CD5-, CD7+, CD30+, CD56+, CD103+, CD8+/-, and TCR beta+/-

## Electrocardiogram
- There are no ECG findings associated with enteropathy-associated T cell lymphoma.

## X-ray
- There are no x-ray findings associated with enteropathy-associated T cell lymphoma.

## Echocardiography or Ultrasound
- There are no echocardiography/ultrasound findings associated with enteropathy-associated T cell lymphoma.

## CT scan
- CT scan may be helpful in the diagnosis of enteropathy-associated T-cell lymphoma.
- Findings on CT scan suggestive of enteropathy-associated T-cell lymphoma include:
- Bowel wall thickening
- Mesenteric fat infiltration
- Mesenteric lymph node cavitation
- Intussusception
- Small-sized spleen

## MRI
- MRI may be helpful in the diagnosis of enteropathy-associated T-cell lymphoma, especially in those EATL involved epithelial layers of the small intestine and also for response to treatment

## Other Imaging Findings
- Other diagnostic studies for enteropathy-associated T-cell lymphoma include:
- PET scan
- Barium study
- Colonoscopy
- Findings on barium study suggestive of enteropathy-associated T-cell lymphoma include:
- Multiple aphthous ulcers
- Segmental luminal narrowing
- Finding on colonoscopy suggestive of enteropathy-associated T-cell lymphoma includes:
- Aphthous ulcers

## Other Diagnostic Studies
- Other diagnostic studies for enteropathy-associated T-cell lymphoma include:
Bone marrow aspiration
Bone marrow biopsy
- Bone marrow aspiration
- Bone marrow biopsy

# Treatment

## Medical Therapy
- There is no treatment for enteropathy-associated T-cell lymphoma; the mainstay of therapy is supportive care. The optimal therapy for enteropathy-associated T-cell lymphoma depends  on the extent and the location of the lymphoma in the small intestine. Stem cell transplant can be helpful in those patients that are in remission phase of disease.

## Surgery
- Surgery is not the first line treatment option for patients with enteropathy-associated T-cell lymphoma.
- Local debulking is usually reserved for patients with tumor masses with a high risk of obstruction, hemorrhage, and perforation.

## Primary Prevention
- There are no established measures for the primary prevention of enteropathy-associated T cell lymphoma.

## Secondary Prevention
There are no established measures for the secondary prevention of enteropathy-associated T cell lymphoma.