Cystic lymphangioma of the mesentery is a benign condition, probably of malformative origin, and frequently appearing in infancy. Its symptomatology can be very polymorphic. Its diagnosis is suspected by ultrasonography and computed tomography, and definitely confirmed by pathology. About a recent case of cystic lymphangioma of the mesentery diagnosed and operated on at the university hospital of Liège in an adult patient, the authors review its classification and its therapeutic strategy. Surgical resection is indicated in symptomatic cystic lymphangioma.