An unusual etiology of diarrhea: primary intestinal lymphangiectasia.

Primary intestinal lymphangiectasia (PIL) is a rare disorder characterized by malformed and dilated intestinal lymphatic vessels, resulting in impaired drainage and leakage of lymph fluid into the gastrointestinal lumen. This leads to protein-losing enteropathy, causing chronic diarrhea, peripheral edema, weight loss, and hypoalbuminemia due to loss of proteins, lymphocytes, and lipids. Diagnosis relies on endoscopic visualization of pathognomonic white mucosal plaques (representing dilated lymphatics) and histopathological confirmation of lymphatic dilation, after excluding secondary causes like malignancy, surgery, or inflammatory conditions.