Primary intestinal lymphangiectasia (PIL) is a rare disorder characterized by 
dilated intestinal lacteals resulting in lymph leakage into the small bowel 
lumen and responsible for protein-losing enteropathy leading to lymphopenia, 
hypoalbuminemia and hypogammaglobulinemia. PIL is generally diagnosed before 3 
years of age but may be diagnosed in older patients. Prevalence is unknown. The 
main symptom is predominantly bilateral lower limb edema. Edema may be moderate 
to severe with anasarca and includes pleural effusion, pericarditis or chylous 
ascites. Fatigue, abdominal pain, weight loss, inability to gain weight, 
moderate diarrhea or fat-soluble vitamin deficiencies due to malabsorption may 
also be present. In some patients, limb lymphedema is associated with PIL and is 
difficult to distinguish lymphedema from edema. Exsudative enteropathy is 
confirmed by the elevated 24-h stool alpha1-antitrypsin clearance. Etiology 
remains unknown. Very rare familial cases of PIL have been reported. Diagnosis 
is confirmed by endoscopic observation of intestinal lymphangiectasia with the 
corresponding histology of intestinal biopsy specimens. Videocapsule endoscopy 
may be useful when endoscopic findings are not contributive. Differential 
diagnosis includes constrictive pericarditis, intestinal lymphoma, Whipple's 
disease, Crohn's disease, intestinal tuberculosis, sarcoidosis or systemic 
sclerosis. Several B-cell lymphomas confined to the gastrointestinal tract 
(stomach, jejunum, midgut, ileum) or with extra-intestinal localizations were 
reported in PIL patients. A low-fat diet associated with medium-chain 
triglyceride supplementation is the cornerstone of PIL medical management. The 
absence of fat in the diet prevents chyle engorgement of the intestinal 
lymphatic vessels thereby preventing their rupture with its ensuing lymph loss. 
Medium-chain triglycerides are absorbed directly into the portal venous 
circulation and avoid lacteal overloading. Other inconsistently effective 
treatments have been proposed for PIL patients, such as antiplasmin, octreotide 
or corticosteroids. Surgical small-bowel resection is useful in the rare cases 
with segmental and localized intestinal lymphangiectasia. The need for dietary 
control appears to be permanent, because clinical and biochemical findings 
reappear after low-fat diet withdrawal. PIL outcome may be severe even 
life-threatening when malignant complications or serous effusion(s) occur.