This report describes two patients with sporadic lymphangioleiomyomatosis complicated by protein-losing enteropathy (PLE). Imaging studies indicated retroperitoneal lymphangioleiomyomas and abnormalities of the adjacent digestive tract. Endoscopic mucosal biopsy revealed colonic lymphangiectasia in one patient; whereas the site in the other patient was intestinal. Treatment with sirolimus led to the complete resolution of PLE within several months; additionally, marked shrinkage was observed in the lymphangioleiomyomas of both cases. These findings suggest that colonic or intestinal lymphatic congestion due to neighboring lymphangioleiomyomas was the mechanism for the development of PLE. At the time of writing this report, the beneficial effect of sirolimus has lasted for more than 3 years.