Lymphangioma is an uncommon tumor. Lymphangiomatosis, a benign tumor consisting of a cluster of dilated lymphatic channels, is very unusual. Most lymphangiomatoses are found in the neck and head area. Less than 5% are diagnosed intraabdominally and they are very infrequently encountered in the retroperitoneal area. Herein, we report a rare case of a 32 year-old woman who had disseminated intra-abdominal and retroperitoneal cystic lymphangiomatosis, which presented as acute abdomen. She received exploratory laparotomy due to the suspicion of malignancy, which was finally confirmed as cystic lymphangiomatosis. The clinical manifestations, imaging features, and management of this patient are discussed and compared with previous literature.