A 39-year-old female patient with progressive abdominal distension underwent an US exam which showed large volume ascites in the abdomen. The clinical and imaging findings were concerning for peritoneal carcinomatosis. Axial plane CT image after IV and oral contrast use reveals a large cystic lesion insinuating between the mesenteric leaves. This cystic mass was separating apart the adjacent bowel loops (stars). Also noted were internal septations (arrows) within this large cystic mass. Surgical and subsequent histopathological examinations confirmed large mesenteric lymphangioma.