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.