are observed more frequently in women, with only four cases having been found in men. Even though mucinous cystadenoma are common ovarian tumor, what makes PRMC so rare is their retroperitoneal location. PRMC and benign mucinous cystadenoma of the ovary are microscopically similar. Both are multiloculated cystic neoplasms and are lined by a single layer of tall columnar cells with a clear basal nucleus and cytoplasm. Both of them have identical histochemical and ultrastructural features. Flat to low cuboidal cells, resembling mesothelial cells, in the lining interspersed between columnar cells in the same area is the only histological difference between the two tumors. See also Mucinous adenocarcinoma References External links Types of neoplasia