Abstract
Endosalpingiosis is a nonneoplastic lesion defined by the presence of tubal epithelium at ectopic sites such as the peritoneum, bladder, appendix, and even uterus. They may be asymptomatic and detected incidentally on ultrasonography. However, cystic endosalpingiosis is also known to be a mimicker of ovarian neoplasms. It is crucial for both the clinician and the pathologist to be aware of this benign lesion so that overdiagnosis and overtreatment can be avoided. We report a case of endosalpingiosis of the uterine serosa in a 45-year-old woman which was misdiagnosed as an adnexal cyst on radiological investigations.