Retroperitoneal mucinous cystadenoma with borderline focuses is an extremely rare tumor. So far, only 14 cases have been reported in the literature , all but one among them were reported in women. Our observation concerns the second male patient affected with this pathological disorder (worldwide). The characteristics of the reported cases are summarized in table 1. Cases include women aged 17 to 48 years and one man who was 63. The mean age is 39 years., All patients were admitted for flank pain with an abdominal distension. Unlike the above cases, the patient subject of the present study, who was 44, presented abdominal pains with a right hypochondric process.
Radiologically, retroperitoneal mucinous cystadenoma presents a cystic formation, uni or bilocular repressing the organs around .
The differential diagnosis with retroperitoneal mucinous cystadenoma is made with lymphangioma, kystic teratoma, lymphocela, urinoma, kystic mesothelioma . The tumor diagnosis lays on anatomopathologic exam .
Macroscopically, we notice several cysts with different sizes from 6 to 33 cm (mean of 14), surrounded by a thin capsule, with no communication with the neighbouring organs. When opened, the cysts have a gelatinous content, they may be uni or multilocular and contain vegetations.
A correct sampling of the resection piece is necessary in order to search for a borderline or a carcinomatous focus .
Microscopically, the tumor resembles ovarian mucinous cystic neoplasms. The cyst locules are lined mainly by a single row of mucin-secreting columnar epithelium. The lining epithelium show mild to moderate stratification (not more than 4 layers thick) with mild to moderate cytologic atypia with no evidence of stromal invasion.
The immunohistochemitry analysis shows a positive match to CK7 and CK20 antibodies. This is the same profile encounted in ovary mucinous tumors .
The histogenesis of this tumor is still unkown. Several theories do exist. For some authors , retroperitoneal mucinous cystadenoma develops at the expense of ectopic or auxiliary ovary in retroperitoneal position. For others, the origin is a monodermic teratoma with mucinous epithelium proliferation .
The latest hypothesis concerns a metaplasic origin of the cysts: they may develop from a coelomic epithelium . During the embryogenesis, coelomic epithelium converts to peritoneal mesothelium and ovarian germinal epithelium. Peritoneal mesothelium seems to keep the same differentiation properties than ovarian epithelial tumors . The similarity of immunohistochemical and ultrastructural profiles with ovarian mucinous tumors supports this hypothesis.
The management of this tumor requires a large surgical exeresis by a complete enucleation [2, 8, 9], with a long term follow up, especially when borderline foci are found, to prevent relapses or malignant degeneration .
The postoperative evolution is generally well . One case on 14 developed metastases to mediastinal lymph nodes, 4 years after surgery, and another presented a paraovarian relapse 21 months after the resection.