Report of a case: Retroperitoneal mucinous cystadenocarcinoma with rapid progression

Introduction Retroperitoneal mucinous cystic neoplasms are uncommon, and little is known about the etiology of the disease. Malignant forms of these are extremely rare. Here, we report a case of primary retroperitoneal mucinous cystadenocarcinoma (PRMC), which demonstrated unexpectedly aggressive progression despite finding only a limited area of adenocarcinoma.