Pseudomyxoma peritonei is a rare clinical condition that is characterized by the presence of mucinous ascitis. It is believed to originate predominately from a mucinous neoplasm of the appendix including a heterogeneous group of tumours ranging from indolentto malignant. It was first described in the late 19th century. Pseudomyxoma retroperitonei is extremely rare with only 33 cases having been reported since the first description in the middle of the 20th century. We report two additional cases of pseudomyxoma retroperitonei and present a review of the literature.