title: Intestinal metaplasia of appendiceal endometriosis is not uncommon and may mimic appendiceal mucinous neoplasm.
abstract: Endometriosis of the appendix can be an incidental finding or a cause of appendicitis, intussusception, perforation or retention mucocele. Intestinal metaplasia of appendiceal endometriosis may occur, which can lead to a misdiagnosis of low-grade appendiceal mucinous neoplasm. On a retrospective search of the pathology database from 2001 to 2015, we identified 78 appendiceal endometriosis cases and intestinal metaplasia was present in 10/78 (13%) cases. In most of the cases (90%), the foci of intestinal metaplasia were mainly localized close to the mucosa. Intestinal and endometrial hybrid glands were present in 9/10 (90%) cases. These cases were often associated with marked appendiceal distortion, luminal obliteration and mass formation, causing concern for a mucinous neoplasm clinically and pathologically. Our findings indicate that intestinal metaplasia in appendiceal endometriosis is not an uncommon phenomenon, which can be mistaken for a mucinous neoplasm. Endometriosis should be kept in mind when a diagnosis of appendiceal mucinous neoplasm is made, especially in a young woman with a clinical history of endometriosis.
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, CT USA.
authors.forename: Monika
authors.initials: M
authors.lastname: Vyas
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, CT USA.
authors.forename: Serena
authors.initials: S
authors.lastname: Wong
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, CT USA. Electronic address: xuchen.zhang@yale.edu.
authors.forename: Xuchen
authors.initials: X
authors.lastname: Zhang
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000473:pathology*; D000328:Adult; D001063:Appendiceal Neoplasms / Q000473:pathology*; D002429:Cecal Diseases / Q000473:pathology*; D016208:Databases, Factual; D003937:Diagnosis, Differential; D004715:Endometriosis / Q000473:pathology*; D005260:Female; D006801:Humans; D007422:Intestines / Q000473:pathology*; D008679:Metaplasia / Q000473:pathology; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
keywords: Appendix; Endometriosis; Intestinal metaplasia; Mucinous neoplasm