Primary intestinal lymphangiectasia (PIL) is a rare disorder characterized by 
dilated intestinal lymphatics and the development of protein-losing enteropathy. 
Patients with PIL develop hypoalbuminemia, hypocalcemia, lymphopenia and 
hypogammaglobulinemia, and present with bilateral lower limb edema, fatigue, 
abdominal pain and diarrhea. Endoscopy reveals diffusely elongated, 
circumferential and polypoid mucosae covered with whitish enlarged villi, all of 
which indicate intestinal lymphangiectasia. Diagnosis is confirmed by 
characteristic tissue pathology, which includes dilated intestinal lymphatics 
with diffusely swollen mucosa and enlarged villi. The prevalence of PIL has 
increased since the introduction of capsule endoscopy. The etiology and 
prevalence of PIL remain unknown. Some studies have reported that several genes 
and regulatory molecules for lymphangiogenesis are related to PIL. We report the 
case of a patient with PIL involving the entire small bowel that was confirmed 
by capsule endoscopy and double-balloon enteroscopy-guided tissue pathology who 
carried a deletion on chromosome 4q25. The relationship between this deletion on 
chromosome 4 and PIL remains to be investigated.