A subserosal uterus-like mass presenting after a sliding hernia of the ovary and endometriosis: a rare entity with a discussion of the histogenesis.

Objective: To report the first case of a subserosal uterus-like mass.

Design: Case report.

Setting: A community-based hospital.

Patient(s): A 44-year-old nulliparous woman who complained of a left inguinal mass had a medical history that was notable for two features. One was left oophorectomy for a sliding hernia at 10 months of age; the other was endometriosis at the oophorectomy site at 26 years of age.

Intervention(s): Tumorectomy.

Main Outcome Measure(s): Not applicable.

Result(s): Pathologic examination demonstrated that this subserosal mass mimicked a miniature uterus with a leiomyomatous lesion.

Conclusion(s): As of September 2010, 23 cases of uterus-like mass had been reported. Three pathologic theories of uterus-like mass have been proposed: [1] congenital anomaly theory, [2] metaplasia theory, and [3] heterotopia. The pathogenesis of this rare entity is currently under debate. Most uterus-like masses have been connected to the genital organs (75.0%) and associated with endometriosis (50.0%). In the present case, the uterus-like mass developed at the surgical scar site of oophorectomy for a sliding hernia and a tumorectomy for endometriosis. We review the literature and discuss the theories regarding the histogenesis of uterus-like mass.