Retroperitoneal benign lipomas are extremely rare and represent about 2.9% of all primary retroperitoneal tumors.About 80% of the tumors in the retroperitoneal cavities are malignant paper lantern texture neoplasms.We experienced a case of a retroperitoneal lipoma simulating an ovarian mature cystic teratoma.
A diagnosis was correctly made by magnetic resonance imaging (MRI) prior to surgery, and a total tumorectomy was performed.The retroperitoneal lipoma 5th marine division patch was recognized to have arisen from the urinary bladder.Histological sections revealed a tumor consisting of typical adipose cells without atypia.These types of lipomas should be carefully followed-up because they often recur and undergo malignant transformations.