Abstract
Background: Soft-tissue sarcomas may develop in the retroperitoneal space, in the peritoneal cavity and in the lower extremities. They are rare tumors, and make up 1% of all adult malignancies. Complete resection of the tumor is of crucial importance to achieve a long-term survival. Multivisceral resections are required in the majority of cases. Mucinous cystadenoma of the appendix is an uncommon condition, too. Most of the patients with mucinous cystadenoma present with clinical symptoms of acute appendicitis. The diagnosis is usually made postoperatively by histopathological examination. Case Report: We here present a rare co-existence of a retroperitoneal liposarcoma and an appendiceal mucinous cystadenoma. Conclusion: En bloc resection of retroperitoneal soft-tissue sarcomas also provides removal of invaded adjacent organs with any co-existing disease.