Primary intestinal lymphangiectasia is a digestive disorder in which the lymph vessels supplying the lining of the small intestine are enlarged. The cause of the condition is still unknown. The signs and symptoms include swelling of the legs and abdominal discomfort, loss of lymphatic fluid into the gastrointestinal tract, protein-losing enteropathy, too little albumin in the blood, reduced levels of antibodies, and immunodeficiency. Treatment involves a special long-term diet.

Unfortunately, there is no cure for primary intestinal lymphangiectasia (PIL). It is typically managed through dietary restrictions, including a low-fat diet and supplementation of a specific type of fat more easily absorbed by individuals with this condition (medium chain triglycerides). These restrictions usually continue throughout life. Periodic intravenous (IV) infusion of a protein called albumin may be useful in treating swelling of the lower limbs and/or buildup of excess bodily fluids. Use of certain hormones, such as octreotide, may be useful in treating individuals not responding to dietary changes. Surgery is usually not needed unless the disease is limited to one area of the intestine.