Intestinal lymphangiectasia is a disease characterized by a protein-losing enteropathy (hypoproteinemia and edema) and lymphocytopenia due to intestinal lymphatic dilation and subsequent loss of protein-rich lymphatic fluid via the gastrointestinal tract.

The symptoms and laboratory findings are reflective of this protein loss: anasarca and bowel edema due to hypoalbuminemia, immunocompromise due to hypogammaglobulinemia, hypolipidemia, and malabsorptive diarrhea with subsequent nutritional deficiencies due to bowel edema.
 
Primary intestinal lymphangiectasia typically presents as a watery diarrhea, edema, and failure to thrive in the first decade of life. In adults, intestinal lymphangiectasia can be caused by many conditions (see differential diagnosis) including autoimmune, malignant, inflammatory, and vascular disease processes.