RETROPERITONEAL SEROUS CYST WITH ELEVATED LEVELS OF TUMOR MARKERS IN THE CYST FLUID

Retroperitoneal masses are commonly solid tumors, and rarely cystic ones. In the present paper, we report a case of retroperitoneal serous cyst. A 51-year-old woman complaining of an abdominal tumor visited another hospital and was referred to the hospital, because an abdominal cystic lesion was demonstrated by ultrasonography. The retroperitoneal serous cyst was suspected on various imaging studies and an operation was performed. The tumor was a unilocular cyst 12×6×6cm in diameter, without adhesion to the surrounding tissues. It could be extirpated easily. The specimen weighted 420g. The cyst contained colorless and clear serous fluid, and the cystic wall was thin and was covered with a layer of cylindrical epithlium. Retroperitoneal serous cyst was diagnosed. The levels of CEA and CA125 in the cyst fluid were high, and immunohistological stainings for CEA and CA125 were positive in the epithelium of the cyst. In a review of the literature, the origin of the retroperitoneal serous cyst was mainly discussed, and it was inferred that the origin in the present case might be the remnant of Mullerian duct at the embryonal stage.