Mesenteric lymphangioma is one of the least frequently encountered types of benign tumor. This case report concerns a 31-year-old pregnant woman with a mesenteric cystic lymphangioma in the ileum. The multiloculated cystic mass was noted near the uterus by CT before the patient became pregnant. After becoming pregnant, she was followed without treatment for the asymptomatic mass. At 25 weeks' gestation, however, she underwent emergency surgical treatment for small bowel obstruction. Concomitant small bowel resection was performed to remove the cyst. Herein we review seven reported cases of mesenteric benign tumor in pregnancy and explore the clinical features.