Primary mucinous cystoadenocarcinoma of the retroperitoneum: two cases.

Two cases of primary retroperitoneal mucinous cystoadenocarcinoma of the ovarian type are reported. Both tumors occurred in females with bilateral normal ovaries and contained benign, borderline, and malignant mucinous epithelium. Full-thickness infiltration of the cyst wall was not found. In addition to surgery, one patient was given chemotherapy because of spillage from the tumor during intervention. There were no recurrences and no evidence of metastatic disease 19 and 33 months after diagnosis. Histologic findings suggest that the tumors had developed through mucinous metaplasia in preexisting mesothelial cysts.