Appendiceal endosalpingiosis: clinical presentation and imaging appearance of a rare condition of the appendix.

Endosalpingiosis rarely affects the appendix but can be mistaken for acute appendicitis or appendiceal tumors. The medical literature regarding appendiceal endosalpingiosis is sparse; consisting of only four case reports which are primarily focused on the histopathology but provide little radiologic correlation. Endosalpingiosis is a rare condition characterized by the presence of benign fallopian tubal-like glandular epithelium derived from Mullerian ducts, usually affecting the serosal surfaces of the pelvis and peritoneum. It is histologically differentiated from endometriosis as endosalpingiosis lacks endometrial stroma. Endosalpingiosis tends to affect older women and has been associated with ovarian serous tumors of low malignant potential. After a retrospective review of a pathology database, we present pathologically proven cases of appendiceal endosalpingiosis with correlative imaging. We discuss the clinical presentation, illustrate the CT and MRI appearance, histologic characteristics, and review the current medical literature of appendiceal endosalpingiosis.