[Retroperitoneal mucinous cystadenocarcinoma associated with horseshoe kidney: a case report].

We report a case of retroperitoneal mucinous cystadenocarcinoma in a patient with a horseshoe kidney. A 61-year-old woman was admitted to our hospital for examination and therapy of an abdominal mass. Various examinations revealed, a retroperitoneal tumor and a horseshoe kidney. Open surgery was performed. Pathological findings revealed mucinous cystadenocarcinoma. We review and discuss 17 cases of retroperitoneal mucinous cystadenocarcinoma, which have been reported in Japan.