Primary retroperitoneal mucinous cystadenoma (PRMC) is an extremely rare tumor: its histogenesis and its biological behavior remain speculative. Since most retroperitoneal tumors are malignant, a preoperative diagnosis of benignity is essential and it can be reached through imaging examinations, allowing a conservative management approach. We describe the case of a 52-year-old woman with abdominal pain and a palpable mass. Computed tomography of the abdomen revealed a retroperitoneal cystic mass, which was resected successfully through laparoscopy and diagnosed as PRMC. Although there are no pathognomonic, clinical or radiological findings for PRMC, it should be included in the list of differential diagnoses and its imaging criteria of benignity should always be sought, with the aim to exclude malignant tumors.
Keywords: benign retroperitoneal tumor; cystic; mucinous cystadenoma; primary retroperitoneal mucinous tumors; radiological features; radiology; retroperitoneum.