Enteropathy-associated T-cell lymphoma classification

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.

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

Enteropathy-associated T-cell lymphoma classification

Name	Description
Classical enteropathy-associated T-cell lymphoma (Type I Enteropathy-associated T-cell lymphoma)	Covers 80-90% of all enteropathy-associated T-cell lymphoma cases. Is usually associated with refractory celiac disease that is sometimes accompanied by intestinal ulceration (ulcerative jejunitis) Most show adult onset disease or are diagnosed as having celiac disease in the same clinical episode in which the lymphoma is diagnosed. Frequently has large-cell or pleomorphic cytology. Seldom expresses CD8 and CD56.
Monomorphic enteropathy-associated T-cell lymphoma (Type II enteropathy-associated T-cell lymphoma)	Encountered in Asia and other regions where celiac disease is rare. Is sporadic, seldom associated with celiac disease. Covers 10-20% of all enteropathy-associated T-cell lymphoma cases. Is characterized by monomorphic cytology. Frequent expression of CD8 and CD56. The tumor forms an ulcerating mucosal mass that invades the wall of the intestine. Poor prognosis, death occurs from abdominal complications such as small bowel obstruction, perforation.