Incidental appendiceal mucinous neoplasm mimicking a left adnexal mass

Abstract Introduction Appendiceal mucinous neoplasm is a rare type of appendiceal tumors which can present in a variety of symptoms and is difficult to diagnose. Preoperative diagnosis depends mainly on diagnostic imaging such as ultrasonography and computerized tomography (CT) scan. This uncommon case report discusses an appendiceal mucinous neoplasm mimicking a left adnexal mass on presentation, physical examination and diagnostic imaging findings. Presentation of case This is a 61-year-old female found to have a large left adnexal mass during follow up ultrasonography. The patient refused further imaging, and during laparotomy, she was found to have an appendicular mucocele with normal left and right ovaries. Discussion Appendectomy was done and the final pathology came as appendiceal mucinous neoplasm. Her post-operative course and 3 years follow up were uneventful. Conclusions The equivocal signs and symptoms along with the anatomical position of appendiceal mucocele makes it difficult to diagnose and can mimic other types of tumors. Therefore, it should be considered in the deferential diagnosis of lower abdominal and pelvic masses. Highlights