Abdominal lymphangioma is a rare tumor of the lymphatic vessels. A case of an abdominal cystic lymphangioma identified at 22 weeks of gestation is reported. Ultrasonographic monitoring showed a progressive increase of mass size during the gestation. Pregnancy was terminated at 38 weeks and the newborn was submitted to a laparotomy with resection of all cystic structures. At the present time the infant is three years old and is doing well.