Lymphangioma usually occurs in children and usually involves the skin. Mesenteric lymphangiomas are extremely rare in adults (1,2,3). Lymphangioma of the small-bowel mesentery is rare, representing less than 1% of all lymphangiomas (4). We report a case of a 62-year-old female who presented with abdominal pain, discomfort, nausea and vomiting. Pre-operative tests including abdominal ultrasonography and magnetic resonance imaging were performed, but they could not accurately determine the nature of the tumour. Laparotomy was performed; the tumour was excised completely, and a large cystic tumour of the small bowel mesentery was found. Histopathological examination diagnosed the tumour as a cystic lymphangioma. Lymphangiomas are extremely rare, especially in the abdomen of adults, and are asymptomatic for the most part; they often present as acute abdominal conditions, causing life-threatening complications such as secondary infection, rupture with haemorrhage, and volvulus or intestinal obstruction when the tumour increases in size, requiring emergent surgery. Lymphangioma is often difficult to diagnose, and surgical resection is selected in many cases for both diagnosis and treatment.