Appendicitis mimicking the CT appearance of an appendiceal mucinous neoplasm

Abstract

Occasionally, radiologically diagnosed acute appendicitis is found to harbour underlying appendiceal neoplasm on post-surgical histopathology. Conversely, a situation in which radiologically, the appendix demonstrates features consistent with an underlying tumour but post-operative pathology finds no evidence of neoplastic change is rare. We describe a case of a 50year-old man who presented with a markedly dilated "mass-like" appendix with minimal inflammatory changes on a computed tomography scan. Radiological findings were suspicious for an appendiceal neoplasm/mucocele (i.e. low-grade mucinous neoplasm). However, the postsurgical histopathological diagnosis did not concur with the radiological diagnosis and instead demonstrated findings compatible with acute appendicitis without neoplastic change. In this case report we provide a histopathological correlation and an explanation as to how this may have happened with the hope of helping radiologists avoid this pitfall in the future.