Primary retroperitoneal mucinous cystadenoma.

Primary mucinous neoplasms of the retroperitoneum, including mucinous cystadenocarcinomas, mucinous borderline tumors, and mucinous cystadenomas are uncommon tumors found exclusively in women. Since the retroperitoneum does not contain mucinous epithelium, the origin, and histogenesis of these tumors remain unclear. It is speculated that these tumors can arise from teratomas, supernumerary ovaries, or mucinous metaplasia of the retroperitoneal mesothelium. We describe a case of a primary mucinous cystadenoma of the retroperitoneum in a 44 year-old female that presented as a palpable abdominal mass. There was no evidence of recurrence 16 months after complete laparoscopic excision of the tumor. The morphology and immunohistochemical analysis in this case support the hypothesis that mucinous metaplasia of the retroperitoneal mesothelium overlying a preceding inclusion cyst can give rise to retroperitoneal mucinous tumors.