Statement I is false: While mesenteric cysts can occur in children, they are relatively rare overall and are not considered to occur most commonly in the pediatric population. They can be found in individuals of all ages.
Statement II is false: The most common presentation of mesenteric cysts is often an asymptomatic abdominal mass that is discovered incidentally during a physical examination or imaging for other reasons. When symptoms do occur, they are usually due to the size or complications of the cyst and can include vague abdominal discomfort, distension, or a palpable, mobile mass. Pain is not the most common initial presentation, and the location of the swelling can vary depending on the location of the cyst within the mesentery, not necessarily near the umbilicus.