Huge primary mucinous cystadenoma of the retroperitoneum mimicking a left ovarian tumor.

Primary mucinous cystic tumors of the retroperitoneum are rarely encountered and have been reported in approximately 25 cases in the literature. The histogenesis of primary mucinous cystadenomas is not clear. Most authors suggest that it develops through mucinous metaplasia in a pre-existing mesothelium-lined cyst. Surgery is the only treatment. In this report we present an additional case of primary retroperitoneal mucinous cystadenoma in a 44-year-old female.